sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <[e-mail]>
Acked-by: Andrey Ignatov <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

arch/arm64/kernel/armv8_deprecated.c

···
 }
 
 static int emulation_proc_handler(struct ctl_table *table, int write,
-				  void __user *buffer, size_t *lenp,
+				  void *buffer, size_t *lenp,
 				  loff_t *ppos)
 {
 	int ret = 0;

arch/arm64/kernel/fpsimd.c

···
 #ifdef CONFIG_SYSCTL
 
 static int sve_proc_do_default_vl(struct ctl_table *table, int write,
-				  void __user *buffer, size_t *lenp,
-				  loff_t *ppos)
+				  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 	int vl = sve_default_vl;

arch/mips/lasat/sysctl.c

···
 		len = 0;
 		p = buffer;
 		while (len < *lenp) {
-			if (get_user(c, p++))
-				return -EFAULT;
+			c = *p;
+			p++;
 			if (c == 0 || c == '\n')
 				break;
 			len++;
 		}
 		if (len >= sizeof(ipbuf)-1)
 			len = sizeof(ipbuf) - 1;
-		if (copy_from_user(ipbuf, buffer, len))
-			return -EFAULT;
+		memcpy(ipbuf, buffer, len);
 		ipbuf[len] = 0;
 		*ppos += *lenp;
 		/* Now see if we can convert it to a valid IP */
···
 		if (len > *lenp)
 			len = *lenp;
 		if (len)
-			if (copy_to_user(buffer, ipbuf, len))
-				return -EFAULT;
+			memcpy(buffer, ipbuf, len);
 		if (len < *lenp) {
-			if (put_user('\n', ((char *) buffer) + len))
-				return -EFAULT;
+			*((char *)buffer + len) = '\n';
 			len++;
 		}
 		*lenp = len;

arch/s390/appldata/appldata_base.c

···
  */
 static const char appldata_proc_name[APPLDATA_PROC_NAME_LENGTH] = "appldata";
 static int appldata_timer_handler(struct ctl_table *ctl, int write,
-				  void __user *buffer, size_t *lenp, loff_t *ppos);
+				  void *buffer, size_t *lenp, loff_t *ppos);
 static int appldata_interval_handler(struct ctl_table *ctl, int write,
-					 void __user *buffer,
-					 size_t *lenp, loff_t *ppos);
+				     void *buffer, size_t *lenp, loff_t *ppos);
 
 static struct ctl_table_header *appldata_sysctl_header;
 static struct ctl_table appldata_table[] = {
···
  */
 static int
 appldata_timer_handler(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int timer_active = appldata_timer_active;
 	int rc;
···
  */
 static int
 appldata_interval_handler(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int interval = appldata_interval;
 	int rc;
···
  */
 static int
 appldata_generic_handler(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct appldata_ops *ops = NULL, *tmp_ops;
 	struct list_head *lh;

arch/s390/kernel/debug.c

···
  * if debug_active is already off
  */
 static int s390dbf_procactive(struct ctl_table *table, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+			      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!write || debug_stoppable || !debug_active)
 		return proc_dointvec(table, write, buffer, lenp, ppos);

arch/s390/kernel/topology.c

···
 early_param("topology", topology_setup);
 
 static int topology_ctl_handler(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int enabled = topology_is_enabled();
 	int new_mode;

arch/s390/mm/cmm.c

···
 }
 
 static int cmm_pages_handler(struct ctl_table *ctl, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	long nr = cmm_get_pages();
 	struct ctl_table ctl_entry = {
···
 }
 
 static int cmm_timed_pages_handler(struct ctl_table *ctl, int write,
-				   void __user *buffer, size_t *lenp,
+				   void *buffer, size_t *lenp,
 				   loff_t *ppos)
 {
 	long nr = cmm_get_timed_pages();
···
 }
 
 static int cmm_timeout_handler(struct ctl_table *ctl, int write,
-			       void __user *buffer, size_t *lenp, loff_t *ppos)
+			       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	char buf[64], *p;
 	long nr, seconds;
···
 
 	if (write) {
 		len = min(*lenp, sizeof(buf));
-		if (copy_from_user(buf, buffer, len))
-			return -EFAULT;
+		memcpy(buf, buffer, len);
 		buf[len - 1] = '\0';
 		cmm_skip_blanks(buf, &p);
 		nr = simple_strtoul(p, &p, 0);
···
 			      cmm_timeout_pages, cmm_timeout_seconds);
 		if (len > *lenp)
 			len = *lenp;
-		if (copy_to_user(buffer, buf, len))
-			return -EFAULT;
+		memcpy(buffer, buf, len);
 		*lenp = len;
 		*ppos += len;
 	}

arch/x86/kernel/itmt.c

···
 unsigned int __read_mostly sysctl_sched_itmt_enabled;
 
 static int sched_itmt_update_handler(struct ctl_table *table, int write,
-				     void __user *buffer, size_t *lenp,
-				     loff_t *ppos)
+				     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned int old_sysctl;
 	int ret;

drivers/cdrom/cdrom.c

···
 }
 
 static int cdrom_sysctl_handler(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 	

drivers/char/random.c

···
  * sysctl system call, as 16 bytes of binary data.
  */
 static int proc_do_uuid(struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+			void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table fake_table;
 	unsigned char buf[64], tmp_uuid[16], *uuid;

drivers/macintosh/mac_hid.c

···
 }
 
 static int mac_hid_toggle_emumouse(struct ctl_table *table, int write,
-				   void __user *buffer, size_t *lenp,
-				   loff_t *ppos)
+				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = table->data;
 	int old_val = *valp;

drivers/parport/procfs.c

···
 #define PARPORT_MAX_SPINTIME_VALUE 1000
 
 static int do_active_device(struct ctl_table *table, int write,
-		      void __user *result, size_t *lenp, loff_t *ppos)
+		      void *result, size_t *lenp, loff_t *ppos)
 {
 	struct parport *port = (struct parport *)table->extra1;
 	char buffer[256];
···
 		*lenp = len;
 
 	*ppos += len;
-
-	return copy_to_user(result, buffer, len) ? -EFAULT : 0;
+	memcpy(result, buffer, len);
+	return 0;
 }
 
 #ifdef CONFIG_PARPORT_1284
 static int do_autoprobe(struct ctl_table *table, int write,
-			void __user *result, size_t *lenp, loff_t *ppos)
+			void *result, size_t *lenp, loff_t *ppos)
 {
 	struct parport_device_info *info = table->extra2;
 	const char *str;
···
 
 	*ppos += len;
 
-	return copy_to_user (result, buffer, len) ? -EFAULT : 0;
+	memcpy(result, buffer, len);
+	return 0;
 }
 #endif /* IEEE1284.3 support. */
 
 static int do_hardware_base_addr(struct ctl_table *table, int write,
-				 void __user *result,
-				 size_t *lenp, loff_t *ppos)
+				 void *result, size_t *lenp, loff_t *ppos)
 {
 	struct parport *port = (struct parport *)table->extra1;
 	char buffer[20];
···
 		*lenp = len;
 
 	*ppos += len;
-
-	return copy_to_user(result, buffer, len) ? -EFAULT : 0;
+	memcpy(result, buffer, len);
+	return 0;
 }
 
 static int do_hardware_irq(struct ctl_table *table, int write,
-			   void __user *result,
-			   size_t *lenp, loff_t *ppos)
+			   void *result, size_t *lenp, loff_t *ppos)
 {
 	struct parport *port = (struct parport *)table->extra1;
 	char buffer[20];
···
 		*lenp = len;
 
 	*ppos += len;
-
-	return copy_to_user(result, buffer, len) ? -EFAULT : 0;
+	memcpy(result, buffer, len);
+	return 0;
 }
 
 static int do_hardware_dma(struct ctl_table *table, int write,
-			   void __user *result,
-			   size_t *lenp, loff_t *ppos)
+			   void *result, size_t *lenp, loff_t *ppos)
 {
 	struct parport *port = (struct parport *)table->extra1;
 	char buffer[20];
···
 		*lenp = len;
 
 	*ppos += len;
-
-	return copy_to_user(result, buffer, len) ? -EFAULT : 0;
+	memcpy(result, buffer, len);
+	return 0;
 }
 
 static int do_hardware_modes(struct ctl_table *table, int write,
-			     void __user *result,
-			     size_t *lenp, loff_t *ppos)
+			     void *result, size_t *lenp, loff_t *ppos)
 {
 	struct parport *port = (struct parport *)table->extra1;
 	char buffer[40];
···
 		*lenp = len;
 
 	*ppos += len;
-
-	return copy_to_user(result, buffer, len) ? -EFAULT : 0;
+	memcpy(result, buffer, len);
+	return 0;
 }
 
 #define PARPORT_PORT_DIR(CHILD) { .procname = NULL, .mode = 0555, .child = CHILD }

fs/dcache.c

···
 	return sum < 0 ? 0 : sum;
 }
 
-int proc_nr_dentry(struct ctl_table *table, int write, void __user *buffer,
+int proc_nr_dentry(struct ctl_table *table, int write, void *buffer,
 		   size_t *lenp, loff_t *ppos)
 {
 	dentry_stat.nr_dentry = get_nr_dentry();

fs/drop_caches.c

···
 }
 
 int drop_caches_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	int ret;
 

fs/file_table.c

···
  */
 #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
 int proc_nr_files(struct ctl_table *table, int write,
-                     void __user *buffer, size_t *lenp, loff_t *ppos)
+                     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	files_stat.nr_files = get_nr_files();
 	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 }
 #else
 int proc_nr_files(struct ctl_table *table, int write,
-                     void __user *buffer, size_t *lenp, loff_t *ppos)
+                     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }

fs/fscache/main.c

···
 static struct ctl_table_header *fscache_sysctl_header;
 
 static int fscache_max_active_sysctl(struct ctl_table *table, int write,
-				     void __user *buffer,
-				     size_t *lenp, loff_t *ppos)
+				     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct workqueue_struct **wqp = table->extra1;
 	unsigned int *datap = table->data;

fs/inode.c

···
  */
 #ifdef CONFIG_SYSCTL
 int proc_nr_inodes(struct ctl_table *table, int write,
-		   void __user *buffer, size_t *lenp, loff_t *ppos)
+		   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	inodes_stat.nr_inodes = get_nr_inodes();
 	inodes_stat.nr_unused = get_nr_inodes_unused();

fs/proc/proc_sysctl.c

···
 	return err;
 }
 
-static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
+static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
 		size_t count, loff_t *ppos, int write)
 {
 	struct inode *inode = file_inode(filp);
 	struct ctl_table_header *head = grab_header(inode);
 	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
-	void *new_buf = NULL;
+	void *kbuf;
 	ssize_t error;
 
 	if (IS_ERR(head))
···
 	if (!table->proc_handler)
 		goto out;
 
-	error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, buf, &count,
-					   ppos, &new_buf);
-	if (error)
-		goto out;
-
-	/* careful: calling conventions are nasty here */
-	if (new_buf) {
-		mm_segment_t old_fs;
-
-		old_fs = get_fs();
-		set_fs(KERNEL_DS);
-		error = table->proc_handler(table, write, (void __user *)new_buf,
-					    &count, ppos);
-		set_fs(old_fs);
-		kfree(new_buf);
+	if (write) {
+		kbuf = memdup_user_nul(ubuf, count);
+		if (IS_ERR(kbuf)) {
+			error = PTR_ERR(kbuf);
+			goto out;
+		}
 	} else {
-		error = table->proc_handler(table, write, buf, &count, ppos);
+		error = -ENOMEM;
+		kbuf = kzalloc(count, GFP_KERNEL);
+		if (!kbuf)
+			goto out;
 	}
 
-	if (!error)
-		error = count;
+	error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count,
+					   ppos);
+	if (error)
+		goto out_free_buf;
+
+	/* careful: calling conventions are nasty here */
+	error = table->proc_handler(table, write, kbuf, &count, ppos);
+	if (error)
+		goto out_free_buf;
+
+	if (!write) {
+		error = -EFAULT;
+		if (copy_to_user(ubuf, kbuf, count))
+			goto out_free_buf;
+	}
+
+	error = count;
+out_free_buf:
+	kfree(kbuf);
 out:
 	sysctl_head_finish(head);
 

fs/quota/dquot.c

···
 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
 
 static int do_proc_dqstats(struct ctl_table *table, int write,
-		     void __user *buffer, size_t *lenp, loff_t *ppos)
+		     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned int type = (unsigned long *)table->data - dqstats.stat;
 	s64 value = percpu_counter_sum(&dqstats.counter[type]);

fs/xfs/xfs_sysctl.c

···
 xfs_stats_clear_proc_handler(
 	struct ctl_table	*ctl,
 	int			write,
-	void			__user *buffer,
+	void			*buffer,
 	size_t			*lenp,
 	loff_t			*ppos)
 {
···
 xfs_panic_mask_proc_handler(
 	struct ctl_table	*ctl,
 	int			write,
-	void			__user *buffer,
+	void			*buffer,
 	size_t			*lenp,
 	loff_t			*ppos)
 {

include/linux/bpf-cgroup.h

···
 
 int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
 				   struct ctl_table *table, int write,
-				   void __user *buf, size_t *pcount,
-				   loff_t *ppos, void **new_buf,
+				   void **buf, size_t *pcount, loff_t *ppos,
 				   enum bpf_attach_type type);
 
 int __cgroup_bpf_run_filter_setsockopt(struct sock *sock, int *level,
···
 })
 
 
-#define BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, buf, count, pos, nbuf)  \
+#define BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, buf, count, pos)  \
 ({									       \
 	int __ret = 0;							       \
 	if (cgroup_bpf_enabled)						       \
 		__ret = __cgroup_bpf_run_filter_sysctl(head, table, write,     \
-						       buf, count, pos, nbuf,  \
+						       buf, count, pos,        \
 						       BPF_CGROUP_SYSCTL);     \
 	__ret;								       \
 })
···
 #define BPF_CGROUP_RUN_PROG_UDP6_RECVMSG_LOCK(sk, uaddr) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type,major,minor,access) ({ 0; })
-#define BPF_CGROUP_RUN_PROG_SYSCTL(head,table,write,buf,count,pos,nbuf) ({ 0; })
+#define BPF_CGROUP_RUN_PROG_SYSCTL(head,table,write,buf,count,pos) ({ 0; })
 #define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock, level, optname, optval, \
 				       optlen, max_optlen, retval) ({ retval; })

include/linux/compaction.h

···
 #ifdef CONFIG_COMPACTION
 extern int sysctl_compact_memory;
 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
-			void __user *buffer, size_t *length, loff_t *ppos);
+			void *buffer, size_t *length, loff_t *ppos);
 extern int sysctl_extfrag_threshold;
 extern int sysctl_compact_unevictable_allowed;
 

include/linux/fs.h

···
 
 struct ctl_table;
 int proc_nr_files(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos);
+		  void *buffer, size_t *lenp, loff_t *ppos);
 int proc_nr_dentry(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos);
+		  void *buffer, size_t *lenp, loff_t *ppos);
 int proc_nr_inodes(struct ctl_table *table, int write,
-		   void __user *buffer, size_t *lenp, loff_t *ppos);
+		   void *buffer, size_t *lenp, loff_t *ppos);
 int __init get_filesystem_list(char *buf);
 
 #define __FMODE_EXEC		((__force int) FMODE_EXEC)

include/linux/ftrace.h

···
 extern int __disable_trace_on_warning;
 
 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp,
-			     loff_t *ppos);
+			     void *buffer, size_t *lenp, loff_t *ppos);
 
 #else /* CONFIG_TRACING */
 static inline void  disable_trace_on_warning(void) { }

include/linux/hugetlb.h

···
 void hugepage_put_subpool(struct hugepage_subpool *spool);
 
 void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
-int hugetlb_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
-int hugetlb_overcommit_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
-int hugetlb_treat_movable_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
-
-#ifdef CONFIG_NUMA
-int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
-#endif
+int hugetlb_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *);
+int hugetlb_overcommit_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
+int hugetlb_treat_movable_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
+int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
 
 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
 long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,

include/linux/kprobes.h

···
 #ifdef CONFIG_SYSCTL
 extern int sysctl_kprobes_optimization;
 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
-					     int write, void __user *buffer,
+					     int write, void *buffer,
 					     size_t *length, loff_t *ppos);
 #endif
 extern void wait_for_kprobe_optimizer(void);

include/linux/latencytop.h

···
 
 void clear_tsk_latency_tracing(struct task_struct *p);
 
-extern int sysctl_latencytop(struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos);
+int sysctl_latencytop(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
 
 #else
 

include/linux/mm.h

···
 extern int sysctl_overcommit_ratio;
 extern unsigned long sysctl_overcommit_kbytes;
 
-extern int overcommit_ratio_handler(struct ctl_table *, int, void __user *,
-				    size_t *, loff_t *);
-extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
-				    size_t *, loff_t *);
+int overcommit_ratio_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
+int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
 
 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
 
···
 
 #ifdef CONFIG_SYSCTL
 extern int sysctl_drop_caches;
-int drop_caches_sysctl_handler(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
+int drop_caches_sysctl_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
 #endif
 
 void drop_slab(void);

include/linux/mmzone.h

···
 /* These two functions are used to setup the per zone pages min values */
 struct ctl_table;
 
-int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
-int watermark_scale_factor_sysctl_handler(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
+int min_free_kbytes_sysctl_handler(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
+int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, void *,
+		size_t *, loff_t *);
 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES];
-int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
+int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, void *,
+		size_t *, loff_t *);
 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
+		void *, size_t *, loff_t *);
 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
-			void __user *, size_t *, loff_t *);
+		void *, size_t *, loff_t *);
 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
-			void __user *, size_t *, loff_t *);
-
-extern int numa_zonelist_order_handler(struct ctl_table *, int,
-			void __user *, size_t *, loff_t *);
+		void *, size_t *, loff_t *);
+int numa_zonelist_order_handler(struct ctl_table *, int,
+		void *, size_t *, loff_t *);
 extern int percpu_pagelist_fraction;
 extern char numa_zonelist_order[];
 #define NUMA_ZONELIST_ORDER_LEN	16

include/linux/nmi.h

···
 #endif
 
 struct ctl_table;
-extern int proc_watchdog(struct ctl_table *, int ,
-			 void __user *, size_t *, loff_t *);
-extern int proc_nmi_watchdog(struct ctl_table *, int ,
-			     void __user *, size_t *, loff_t *);
-extern int proc_soft_watchdog(struct ctl_table *, int ,
-			      void __user *, size_t *, loff_t *);
-extern int proc_watchdog_thresh(struct ctl_table *, int ,
-				void __user *, size_t *, loff_t *);
-extern int proc_watchdog_cpumask(struct ctl_table *, int,
-				 void __user *, size_t *, loff_t *);
+int proc_watchdog(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_nmi_watchdog(struct ctl_table *, int , void *, size_t *, loff_t *);
+int proc_soft_watchdog(struct ctl_table *, int , void *, size_t *, loff_t *);
+int proc_watchdog_thresh(struct ctl_table *, int , void *, size_t *, loff_t *);
+int proc_watchdog_cpumask(struct ctl_table *, int, void *, size_t *, loff_t *);
 
 #ifdef CONFIG_HAVE_ACPI_APEI_NMI
 #include <asm/nmi.h>

include/linux/perf_event.h

···
 
 extern void perf_sample_event_took(u64 sample_len_ns);
 
-extern int perf_proc_update_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-extern int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-
+int perf_proc_update_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
+int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
 int perf_event_max_stack_handler(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp, loff_t *ppos);
+		void *buffer, size_t *lenp, loff_t *ppos);
 
 /* Access to perf_event_open(2) syscall. */
 #define PERF_SECURITY_OPEN		0

include/linux/printk.h

···
 extern int dmesg_restrict;
 
 extern int
-devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, void __user *buf,
+devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, void *buf,
 			  size_t *lenp, loff_t *ppos);
 
 extern void wake_up_klogd(void);

include/linux/sched/sysctl.h

···
 extern unsigned long sysctl_hung_task_timeout_secs;
 extern unsigned long sysctl_hung_task_check_interval_secs;
 extern int sysctl_hung_task_warnings;
-extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
-					 void __user *buffer,
-					 size_t *lenp, loff_t *ppos);
+int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
 #else
 /* Avoid need for ifdefs elsewhere in the code */
 enum { sysctl_hung_task_timeout_secs = 0 };
···
 extern __read_mostly unsigned int sysctl_sched_nr_migrate;
 
 int sched_proc_update_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *length,
-		loff_t *ppos);
+		void *buffer, size_t *length, loff_t *ppos);
 #endif
 
 /*
···
 extern int sysctl_sched_rr_timeslice;
 extern int sched_rr_timeslice;
 
-extern int sched_rr_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-
-extern int sched_rt_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-
-#ifdef CONFIG_UCLAMP_TASK
-extern int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
-				       void __user *buffer, size_t *lenp,
-				       loff_t *ppos);
-#endif
-
-extern int sysctl_numa_balancing(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos);
-
-extern int sysctl_schedstats(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos);
+int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
+int sysctl_numa_balancing(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+int sysctl_schedstats(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
 
 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
 extern unsigned int sysctl_sched_energy_aware;
-extern int sched_energy_aware_handler(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos);
+int sched_energy_aware_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
 #endif
 
 #endif /* _LINUX_SCHED_SYSCTL_H */

include/linux/security.h

···
 
 #ifdef CONFIG_MMU
 extern int mmap_min_addr_handler(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp, loff_t *ppos);
+				 void *buffer, size_t *lenp, loff_t *ppos);
 #endif
 
 /* security_inode_init_security callback function to write xattrs */

include/linux/sysctl.h

···
 
 extern const int sysctl_vals[];
 
-typedef int proc_handler (struct ctl_table *ctl, int write,
-			  void __user *buffer, size_t *lenp, loff_t *ppos);
+typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
 
-extern int proc_dostring(struct ctl_table *, int,
-			 void __user *, size_t *, loff_t *);
-extern int proc_dointvec(struct ctl_table *, int,
-			 void __user *, size_t *, loff_t *);
-extern int proc_douintvec(struct ctl_table *, int,
-			 void __user *, size_t *, loff_t *);
-extern int proc_dointvec_minmax(struct ctl_table *, int,
-				void __user *, size_t *, loff_t *);
-extern int proc_douintvec_minmax(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos);
-extern int proc_dointvec_jiffies(struct ctl_table *, int,
-				 void __user *, size_t *, loff_t *);
-extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
-					void __user *, size_t *, loff_t *);
-extern int proc_dointvec_ms_jiffies(struct ctl_table *, int,
-				    void __user *, size_t *, loff_t *);
-extern int proc_doulongvec_minmax(struct ctl_table *, int,
-				  void __user *, size_t *, loff_t *);
-extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
-				      void __user *, size_t *, loff_t *);
-extern int proc_do_large_bitmap(struct ctl_table *, int,
-				void __user *, size_t *, loff_t *);
-extern int proc_do_static_key(struct ctl_table *table, int write,
-			      void __user *buffer, size_t *lenp,
-			      loff_t *ppos);
+int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
+int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
+int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
+		size_t *, loff_t *);
+int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
 
 /*
  * Register a set of sysctl names by calling register_sysctl_table
···
 
 #endif /* CONFIG_SYSCTL */
 
-int sysctl_max_threads(struct ctl_table *table, int write,
-		       void __user *buffer, size_t *lenp, loff_t *ppos);
+int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
 
 #endif /* _LINUX_SYSCTL_H */

include/linux/timer.h

···
 
 extern unsigned int sysctl_timer_migration;
 int timer_migration_handler(struct ctl_table *table, int write,
-			    void __user *buffer, size_t *lenp,
-			    loff_t *ppos);
+			    void *buffer, size_t *lenp, loff_t *ppos);
 #endif
 
 unsigned long __round_jiffies(unsigned long j, int cpu);

include/linux/vmstat.h

···
 #define DISABLE_NUMA_STAT   0
 extern int sysctl_vm_numa_stat;
 DECLARE_STATIC_KEY_TRUE(vm_numa_stat_key);
-extern int sysctl_vm_numa_stat_handler(struct ctl_table *table,
-		int write, void __user *buffer, size_t *length, loff_t *ppos);
+int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *length, loff_t *ppos);
 #endif
 
 struct reclaim_stat {
···
 void refresh_zone_stat_thresholds(void);
 
 struct ctl_table;
-int vmstat_refresh(struct ctl_table *, int write,
-		   void __user *buffer, size_t *lenp, loff_t *ppos);
+int vmstat_refresh(struct ctl_table *, int write, void *buffer, size_t *lenp,
+		loff_t *ppos);
 
 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *);
 

include/linux/writeback.h

···
 extern int block_dump;
 extern int laptop_mode;
 
-extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-extern int dirty_ratio_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
-extern int dirty_bytes_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos);
+int dirty_background_ratio_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
+int dirty_background_bytes_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
+int dirty_ratio_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
+int dirty_bytes_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
 int dirtytime_interval_handler(struct ctl_table *table, int write,
-			       void __user *buffer, size_t *lenp, loff_t *ppos);
-
-struct ctl_table;
-int dirty_writeback_centisecs_handler(struct ctl_table *, int,
-				      void __user *, size_t *, loff_t *);
+		void *buffer, size_t *lenp, loff_t *ppos);
+int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos);
 
 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
 unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);

ipc/ipc_sysctl.c

···
 
 #ifdef CONFIG_PROC_SYSCTL
 static int proc_ipc_dointvec(struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table ipc_table;
 
···
 }
 
 static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table ipc_table;
 
···
 }
 
 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
 	int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
···
 }
 
 static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table ipc_table;
 	memcpy(&ipc_table, table, sizeof(ipc_table));
···
 }
 
 static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table ipc_table;
 	int dummy = 0;

ipc/mq_sysctl.c

···
 }
 
 static int proc_mq_dointvec(struct ctl_table *table, int write,
-			    void __user *buffer, size_t *lenp, loff_t *ppos)
+			    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table mq_table;
 	memcpy(&mq_table, table, sizeof(mq_table));
···
 }
 
 static int proc_mq_dointvec_minmax(struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table mq_table;
 	memcpy(&mq_table, table, sizeof(mq_table));

kernel/bpf/cgroup.c

···
  * @head: sysctl table header
  * @table: sysctl table
  * @write: sysctl is being read (= 0) or written (= 1)
- * @buf: pointer to buffer passed by user space
+ * @buf: pointer to buffer (in and out)
  * @pcount: value-result argument: value is size of buffer pointed to by @buf,
  *	result is size of @new_buf if program set new value, initial value
  *	otherwise
  * @ppos: value-result argument: value is position at which read from or write
  *	to sysctl is happening, result is new position if program overrode it,
  *	initial value otherwise
- * @new_buf: pointer to pointer to new buffer that will be allocated if program
- *	overrides new value provided by user space on sysctl write
- *	NOTE: it's caller responsibility to free *new_buf if it was set
  * @type: type of program to be executed
  *
  * Program is run when sysctl is being accessed, either read or written, and
···
  */
 int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
 				   struct ctl_table *table, int write,
-				   void __user *buf, size_t *pcount,
-				   loff_t *ppos, void **new_buf,
+				   void **buf, size_t *pcount, loff_t *ppos,
 				   enum bpf_attach_type type)
 {
 	struct bpf_sysctl_kern ctx = {
···
 		.new_updated = 0,
 	};
 	struct cgroup *cgrp;
+	loff_t pos = 0;
 	int ret;
 
 	ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL);
-	if (ctx.cur_val) {
-		mm_segment_t old_fs;
-		loff_t pos = 0;
-
-		old_fs = get_fs();
-		set_fs(KERNEL_DS);
-		if (table->proc_handler(table, 0, (void __user *)ctx.cur_val,
-					&ctx.cur_len, &pos)) {
-			/* Let BPF program decide how to proceed. */
-			ctx.cur_len = 0;
-		}
-		set_fs(old_fs);
-	} else {
+	if (!ctx.cur_val ||
+	    table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) {
 		/* Let BPF program decide how to proceed. */
 		ctx.cur_len = 0;
 	}
 
-	if (write && buf && *pcount) {
+	if (write && *buf && *pcount) {
 		/* BPF program should be able to override new value with a
 		 * buffer bigger than provided by user.
 		 */
 		ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL);
 		ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount);
-		if (!ctx.new_val ||
-		    copy_from_user(ctx.new_val, buf, ctx.new_len))
+		if (ctx.new_val) {
+			memcpy(ctx.new_val, *buf, ctx.new_len);
+		} else {
 			/* Let BPF program decide how to proceed. */
 			ctx.new_len = 0;
+		}
 	}
 
 	rcu_read_lock();
···
 	kfree(ctx.cur_val);
 
 	if (ret == 1 && ctx.new_updated) {
-		*new_buf = ctx.new_val;
+		kfree(*buf);
+		*buf = ctx.new_val;
 		*pcount = ctx.new_len;
 	} else {
 		kfree(ctx.new_val);

kernel/events/callchain.c

···
  * sysctl_perf_event_max_contexts_per_stack.
  */
 int perf_event_max_stack_handler(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp, loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *value = table->data;
 	int new_value = *value, ret;

kernel/events/core.c

···
 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
 
 int perf_proc_update_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 	int perf_cpu = sysctl_perf_cpu_time_max_percent;
···
 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
 
 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 

kernel/kprobes.c

···
 static DEFINE_MUTEX(kprobe_sysctl_mutex);
 int sysctl_kprobes_optimization;
 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
-				      void __user *buffer, size_t *length,
+				      void *buffer, size_t *length,
 				      loff_t *ppos)
 {
 	int ret;

kernel/latencytop.c

···
 	return 0;
 }
 
-int sysctl_latencytop(struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+int sysctl_latencytop(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	int err;
 

kernel/pid_namespace.c

···
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
 static int pid_ns_ctl_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct pid_namespace *pid_ns = task_active_pid_ns(current);
 	struct ctl_table tmp = *table;

kernel/printk/printk.c

···
 char devkmsg_log_str[DEVKMSG_STR_MAX_SIZE] = "ratelimit";
 
 int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+			      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	char old_str[DEVKMSG_STR_MAX_SIZE];
 	unsigned int old;

kernel/sched/core.c

···
 #endif
 
 int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	bool update_root_tg = false;
 	int old_min, old_max;
···
 
 #ifdef CONFIG_PROC_SYSCTL
 int sysctl_numa_balancing(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
 	int err;
···
 }
 
 #ifdef CONFIG_PROC_SYSCTL
-int sysctl_schedstats(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+int sysctl_schedstats(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
 	int err;

kernel/sched/fair.c

···
  */
 
 int sched_proc_update_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 	unsigned int factor = get_update_sysctl_factor();

kernel/sched/rt.c

···
 	def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
 }
 
-int sched_rt_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	int old_period, old_runtime;
 	static DEFINE_MUTEX(mutex);
···
 	return ret;
 }
 
-int sched_rr_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	int ret;
 	static DEFINE_MUTEX(mutex);

kernel/sched/topology.c

···
 
 #ifdef CONFIG_PROC_SYSCTL
 int sched_energy_aware_handler(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret, state;
 

kernel/seccomp.c

···
 }
 
 static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,
-					  void __user *buffer, size_t *lenp,
+					  void *buffer, size_t *lenp,
 					  loff_t *ppos)
 {
 	int ret;

kernel/sysctl.c

···
 #ifdef CONFIG_PROC_SYSCTL
 
 static int _proc_do_string(char *data, int maxlen, int write,
-			   char __user *buffer,
-			   size_t *lenp, loff_t *ppos)
+		char *buffer, size_t *lenp, loff_t *ppos)
 {
 	size_t len;
-	char __user *p;
-	char c;
+	char c, *p;
 
 	if (!data || !maxlen || !*lenp) {
 		*lenp = 0;
···
 		*ppos += *lenp;
 		p = buffer;
 		while ((p - buffer) < *lenp && len < maxlen - 1) {
-			if (get_user(c, p++))
-				return -EFAULT;
+			c = *(p++);
 			if (c == 0 || c == '\n')
 				break;
 			data[len++] = c;
···
 		if (len > *lenp)
 			len = *lenp;
 		if (len)
-			if (copy_to_user(buffer, data, len))
-				return -EFAULT;
+			memcpy(buffer, data, len);
 		if (len < *lenp) {
-			if (put_user('\n', buffer + len))
-				return -EFAULT;
+			buffer[len] = '\n';
 			len++;
 		}
 		*lenp = len;
···
  * Returns 0 on success.
  */
 int proc_dostring(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (write)
 		proc_first_pos_non_zero_ignore(ppos, table);
 
-	return _proc_do_string((char *)(table->data), table->maxlen, write,
-			       (char __user *)buffer, lenp, ppos);
+	return _proc_do_string(table->data, table->maxlen, write, buffer, lenp,
+			ppos);
 }
 
 static size_t proc_skip_spaces(char **buf)
···
  * @val: the integer to be converted
  * @neg: sign of the number, %TRUE for negative
  *
- * In case of success %0 is returned and @buf and @size are updated with
- * the amount of bytes written.
+ * In case of success @buf and @size are updated with the amount of bytes
+ * written.
  */
-static int proc_put_long(void __user **buf, size_t *size, unsigned long val,
-			  bool neg)
+static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg)
 {
 	int len;
 	char tmp[TMPBUFLEN], *p = tmp;
···
 	len = strlen(tmp);
 	if (len > *size)
 		len = *size;
-	if (copy_to_user(*buf, tmp, len))
-		return -EFAULT;
+	memcpy(*buf, tmp, len);
 	*size -= len;
 	*buf += len;
-	return 0;
 }
 #undef TMPBUFLEN
 
-static int proc_put_char(void __user **buf, size_t *size, char c)
+static void proc_put_char(void **buf, size_t *size, char c)
 {
 	if (*size) {
-		char __user **buffer = (char __user **)buf;
-		if (put_user(c, *buffer))
-			return -EFAULT;
-		(*size)--, (*buffer)++;
+		char **buffer = (char **)buf;
+		**buffer = c;
+
+		(*size)--;
+		(*buffer)++;
 		*buf = *buffer;
 	}
-	return 0;
 }
 
 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
···
 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
 
 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
-		  int write, void __user *buffer,
+		  int write, void *buffer,
 		  size_t *lenp, loff_t *ppos,
 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
 			      int write, void *data),
···
 {
 	int *i, vleft, first = 1, err = 0;
 	size_t left;
-	char *kbuf = NULL, *p;
+	char *p;
 	
 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
 		*lenp = 0;
···
 
 		if (left > PAGE_SIZE - 1)
 			left = PAGE_SIZE - 1;
-		p = kbuf = memdup_user_nul(buffer, left);
-		if (IS_ERR(kbuf))
-			return PTR_ERR(kbuf);
+		p = buffer;
 	}
 
 	for (; left && vleft--; i++, first=0) {
···
 				break;
 			}
 			if (!first)
-				err = proc_put_char(&buffer, &left, '\t');
-			if (err)
-				break;
-			err = proc_put_long(&buffer, &left, lval, neg);
-			if (err)
-				break;
+				proc_put_char(&buffer, &left, '\t');
+			proc_put_long(&buffer, &left, lval, neg);
 		}
 	}
 
 	if (!write && !first && left && !err)
-		err = proc_put_char(&buffer, &left, '\n');
+		proc_put_char(&buffer, &left, '\n');
 	if (write && !err && left)
 		left -= proc_skip_spaces(&p);
-	if (write) {
-		kfree(kbuf);
-		if (first)
-			return err ? : -EINVAL;
-	}
+	if (write && first)
+		return err ? : -EINVAL;
 	*lenp -= left;
 out:
 	*ppos += *lenp;
···
 }
 
 static int do_proc_dointvec(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos,
+		  void *buffer, size_t *lenp, loff_t *ppos,
 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
 			      int write, void *data),
 		  void *data)
···
 
 static int do_proc_douintvec_w(unsigned int *tbl_data,
 			       struct ctl_table *table,
-			       void __user *buffer,
+			       void *buffer,
 			       size_t *lenp, loff_t *ppos,
 			       int (*conv)(unsigned long *lvalp,
 					   unsigned int *valp,
···
 	int err = 0;
 	size_t left;
 	bool neg;
-	char *kbuf = NULL, *p;
+	char *p = buffer;
 
 	left = *lenp;
 
···
 
 	if (left > PAGE_SIZE - 1)
 		left = PAGE_SIZE - 1;
-
-	p = kbuf = memdup_user_nul(buffer, left);
-	if (IS_ERR(kbuf))
-		return -EINVAL;
 
 	left -= proc_skip_spaces(&p);
 	if (!left) {
···
 		left -= proc_skip_spaces(&p);
 
 out_free:
-	kfree(kbuf);
 	if (err)
 		return -EINVAL;
 
···
 	return err;
 }
 
-static int do_proc_douintvec_r(unsigned int *tbl_data, void __user *buffer,
+static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer,
 			       size_t *lenp, loff_t *ppos,
 			       int (*conv)(unsigned long *lvalp,
 					   unsigned int *valp,
···
 		goto out;
 	}
 
-	err = proc_put_long(&buffer, &left, lval, false);
-	if (err || !left)
+	proc_put_long(&buffer, &left, lval, false);
+	if (!left)
 		goto out;
 
-	err = proc_put_char(&buffer, &left, '\n');
+	proc_put_char(&buffer, &left, '\n');
 
 out:
 	*lenp -= left;
···
 }
 
 static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table,
-			       int write, void __user *buffer,
+			       int write, void *buffer,
 			       size_t *lenp, loff_t *ppos,
 			       int (*conv)(unsigned long *lvalp,
 					   unsigned int *valp,
···
 }
 
 static int do_proc_douintvec(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos,
+			     void *buffer, size_t *lenp, loff_t *ppos,
 			     int (*conv)(unsigned long *lvalp,
 					 unsigned int *valp,
 					 int write, void *data),
···
  *
  * Returns 0 on success.
  */
-int proc_dointvec(struct ctl_table *table, int write,
-		     void __user *buffer, size_t *lenp, loff_t *ppos)
+int proc_dointvec(struct ctl_table *table, int write, void *buffer,
+		  size_t *lenp, loff_t *ppos)
 {
 	return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
 }
 
 #ifdef CONFIG_COMPACTION
 static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table,
-					       int write, void __user *buffer,
-					       size_t *lenp, loff_t *ppos)
+		int write, void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret, old;
 
···
  *
  * Returns 0 on success.
  */
-int proc_douintvec(struct ctl_table *table, int write,
-		     void __user *buffer, size_t *lenp, loff_t *ppos)
+int proc_douintvec(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
 				 do_proc_douintvec_conv, NULL);
···
  * This means we can safely use a temporary.
  */
 static int proc_taint(struct ctl_table *table, int write,
-			       void __user *buffer, size_t *lenp, loff_t *ppos)
+			       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
 	unsigned long tmptaint = get_taint();
···
 
 #ifdef CONFIG_PRINTK
 static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (write && !capable(CAP_SYS_ADMIN))
 		return -EPERM;
···
  * Returns 0 on success or -EINVAL on write when the range check fails.
  */
 int proc_dointvec_minmax(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct do_proc_dointvec_minmax_conv_param param = {
 		.min = (int *) table->extra1,
···
  * Returns 0 on success or -ERANGE on write when the range check fails.
  */
 int proc_douintvec_minmax(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct do_proc_douintvec_minmax_conv_param param = {
 		.min = (unsigned int *) table->extra1,
···
 }
 
 static int proc_dopipe_max_size(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
 				 do_proc_dopipe_max_size_conv, NULL);
···
 }
 
 static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 	if (!error)
···
 
 #ifdef CONFIG_COREDUMP
 static int proc_dostring_coredump(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int error = proc_dostring(table, write, buffer, lenp, ppos);
 	if (!error)
···
 
 #ifdef CONFIG_MAGIC_SYSRQ
 static int sysrq_sysctl_handler(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int tmp, ret;
 
···
 }
 #endif
 
-static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
-				     void __user *buffer,
-				     size_t *lenp, loff_t *ppos,
-				     unsigned long convmul,
-				     unsigned long convdiv)
+static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
+		int write, void *buffer, size_t *lenp, loff_t *ppos,
+		unsigned long convmul, unsigned long convdiv)
 {
 	unsigned long *i, *min, *max;
 	int vleft, first = 1, err = 0;
 	size_t left;
-	char *kbuf = NULL, *p;
+	char *p;
 
 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
 		*lenp = 0;
···
 
 		if (left > PAGE_SIZE - 1)
 			left = PAGE_SIZE - 1;
-		p = kbuf = memdup_user_nul(buffer, left);
-		if (IS_ERR(kbuf))
-			return PTR_ERR(kbuf);
+		p = buffer;
 	}
 
 	for (; left && vleft--; i++, first = 0) {
···
 			*i = val;
 		} else {
 			val = convdiv * (*i) / convmul;
-			if (!first) {
-				err = proc_put_char(&buffer, &left, '\t');
-				if (err)
-					break;
-			}
-			err = proc_put_long(&buffer, &left, val, false);
-			if (err)
-				break;
+			if (!first)
+				proc_put_char(&buffer, &left, '\t');
+			proc_put_long(&buffer, &left, val, false);
 		}
 	}
 
 	if (!write && !first && left && !err)
-		err = proc_put_char(&buffer, &left, '\n');
+		proc_put_char(&buffer, &left, '\n');
 	if (write && !err)
 		left -= proc_skip_spaces(&p);
-	if (write) {
-		kfree(kbuf);
-		if (first)
-			return err ? : -EINVAL;
-	}
+	if (write && first)
+		return err ? : -EINVAL;
 	*lenp -= left;
 out:
 	*ppos += *lenp;
···
 }
 
 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
-				     void __user *buffer,
-				     size_t *lenp, loff_t *ppos,
-				     unsigned long convmul,
-				     unsigned long convdiv)
+		void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul,
+		unsigned long convdiv)
 {
 	return __do_proc_doulongvec_minmax(table->data, table, write,
 			buffer, lenp, ppos, convmul, convdiv);
···
  * Returns 0 on success.
  */
 int proc_doulongvec_minmax(struct ctl_table *table, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
 }
···
  * Returns 0 on success.
  */
 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
-				      void __user *buffer,
-				      size_t *lenp, loff_t *ppos)
+				      void *buffer, size_t *lenp, loff_t *ppos)
 {
     return do_proc_doulongvec_minmax(table, write, buffer,
 				     lenp, ppos, HZ, 1000l);
···
  * Returns 0 on success.
  */
 int proc_dointvec_jiffies(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
     return do_proc_dointvec(table,write,buffer,lenp,ppos,
 		    	    do_proc_dointvec_jiffies_conv,NULL);
···
  * Returns 0 on success.
  */
 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp, loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
     return do_proc_dointvec(table,write,buffer,lenp,ppos,
 		    	    do_proc_dointvec_userhz_jiffies_conv,NULL);
···
  *
  * Returns 0 on success.
  */
-int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos)
+int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
 				do_proc_dointvec_ms_jiffies_conv, NULL);
 }
 
-static int proc_do_cad_pid(struct ctl_table *table, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	struct pid *new_pid;
 	pid_t tmp;
···
  * Returns 0 on success.
  */
 int proc_do_large_bitmap(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int err = 0;
 	bool first = 1;
···
 	}
 
 	if (write) {
-		char *kbuf, *p;
+		char *p = buffer;
 		size_t skipped = 0;
 
 		if (left > PAGE_SIZE - 1) {
···
 			skipped = *lenp - left;
 		}
 
-		p = kbuf = memdup_user_nul(buffer, left);
-		if (IS_ERR(kbuf))
-			return PTR_ERR(kbuf);
-
 		tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
-		if (!tmp_bitmap) {
-			kfree(kbuf);
+		if (!tmp_bitmap)
 			return -ENOMEM;
-		}
 		proc_skip_char(&p, &left, '\n');
 		while (!err && left) {
 			unsigned long val_a, val_b;
···
 			first = 0;
 			proc_skip_char(&p, &left, '\n');
 		}
-		kfree(kbuf);
 		left += skipped;
 	} else {
 		unsigned long bit_a, bit_b = 0;
···
 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
 						   bit_a + 1) - 1;
 
-			if (!first) {
-				err = proc_put_char(&buffer, &left, ',');
-				if (err)
-					break;
-			}
-			err = proc_put_long(&buffer, &left, bit_a, false);
-			if (err)
-				break;
+			if (!first)
+				proc_put_char(&buffer, &left, ',');
+			proc_put_long(&buffer, &left, bit_a, false);
 			if (bit_a != bit_b) {
-				err = proc_put_char(&buffer, &left, '-');
-				if (err)
-					break;
-				err = proc_put_long(&buffer, &left, bit_b, false);
-				if (err)
-					break;
+				proc_put_char(&buffer, &left, '-');
+				proc_put_long(&buffer, &left, bit_b, false);
 			}
 
 			first = 0; bit_b++;
 		}
-		if (!err)
-			err = proc_put_char(&buffer, &left, '\n');
+		proc_put_char(&buffer, &left, '\n');
 	}
 
 	if (!err) {
···
 #else /* CONFIG_PROC_SYSCTL */
 
 int proc_dostring(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_dointvec(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_douintvec(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_dointvec_minmax(struct ctl_table *table, int write,
-		    void __user *buffer, size_t *lenp, loff_t *ppos)
+		    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_douintvec_minmax(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_dointvec_jiffies(struct ctl_table *table, int write,
-		    void __user *buffer, size_t *lenp, loff_t *ppos)
+		    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
-		    void __user *buffer, size_t *lenp, loff_t *ppos)
+		    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_doulongvec_minmax(struct ctl_table *table, int write,
-		    void __user *buffer, size_t *lenp, loff_t *ppos)
+		    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
 
 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
-				      void __user *buffer,
-				      size_t *lenp, loff_t *ppos)
+				      void *buffer, size_t *lenp, loff_t *ppos)
 {
-    return -ENOSYS;
+	return -ENOSYS;
 }
 
 int proc_do_large_bitmap(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return -ENOSYS;
 }
···
 
 #if defined(CONFIG_SYSCTL)
 int proc_do_static_key(struct ctl_table *table, int write,
-		       void __user *buffer, size_t *lenp,
-		       loff_t *ppos)
+		       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct static_key *key = (struct static_key *)table->data;
 	static DEFINE_MUTEX(static_key_mutex);

kernel/time/timer.c

···
 }
 
 int timer_migration_handler(struct ctl_table *table, int write,
-			    void __user *buffer, size_t *lenp,
-			    loff_t *ppos)
+			    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 

kernel/trace/trace.c

···
 }
 
 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp,
+			     void *buffer, size_t *lenp,
 			     loff_t *ppos)
 {
 	int save_tracepoint_printk;

kernel/umh.c

···
 EXPORT_SYMBOL(call_usermodehelper);
 
 static int proc_cap_handler(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
 	unsigned long cap_array[_KERNEL_CAPABILITY_U32S];

kernel/utsname_sysctl.c

···
  *	to observe. Should this be in kernel/sys.c ????
  */
 static int proc_do_uts_string(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table uts_table;
 	int r;

kernel/watchdog.c

···
  * proc_soft_watchdog | soft_watchdog_user_enabled | SOFT_WATCHDOG_ENABLED
  */
 static int proc_watchdog_common(int which, struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int err, old, *param = table->data;
 
···
  * /proc/sys/kernel/watchdog
  */
 int proc_watchdog(struct ctl_table *table, int write,
-		  void __user *buffer, size_t *lenp, loff_t *ppos)
+		  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return proc_watchdog_common(NMI_WATCHDOG_ENABLED|SOFT_WATCHDOG_ENABLED,
 				    table, write, buffer, lenp, ppos);
···
  * /proc/sys/kernel/nmi_watchdog
  */
 int proc_nmi_watchdog(struct ctl_table *table, int write,
-		      void __user *buffer, size_t *lenp, loff_t *ppos)
+		      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!nmi_watchdog_available && write)
 		return -ENOTSUPP;
···
  * /proc/sys/kernel/soft_watchdog
  */
 int proc_soft_watchdog(struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+			void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return proc_watchdog_common(SOFT_WATCHDOG_ENABLED,
 				    table, write, buffer, lenp, ppos);
···
  * /proc/sys/kernel/watchdog_thresh
  */
 int proc_watchdog_thresh(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int err, old;
 
···
  * been brought online, if desired.
  */
 int proc_watchdog_cpumask(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int err;
 

mm/compaction.c

···
  * /proc/sys/vm/compact_memory
  */
 int sysctl_compaction_handler(struct ctl_table *table, int write,
-			void __user *buffer, size_t *length, loff_t *ppos)
+			void *buffer, size_t *length, loff_t *ppos)
 {
 	if (write)
 		compact_nodes();

mm/hugetlb.c

···
 #ifdef CONFIG_SYSCTL
 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
 			 struct ctl_table *table, int write,
-			 void __user *buffer, size_t *length, loff_t *ppos)
+			 void *buffer, size_t *length, loff_t *ppos)
 {
 	struct hstate *h = &default_hstate;
 	unsigned long tmp = h->max_huge_pages;
···
 }
 
 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *length, loff_t *ppos)
+			  void *buffer, size_t *length, loff_t *ppos)
 {
 
 	return hugetlb_sysctl_handler_common(false, table, write,
···
 
 #ifdef CONFIG_NUMA
 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *length, loff_t *ppos)
+			  void *buffer, size_t *length, loff_t *ppos)
 {
 	return hugetlb_sysctl_handler_common(true, table, write,
 							buffer, length, ppos);
···
 #endif /* CONFIG_NUMA */
 
 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
-			void __user *buffer,
-			size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	struct hstate *h = &default_hstate;
 	unsigned long tmp;

mm/page-writeback.c

···
 }
 
 int dirty_background_ratio_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 
···
 }
 
 int dirty_background_bytes_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 
···
 	return ret;
 }
 
-int dirty_ratio_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+int dirty_ratio_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	int old_ratio = vm_dirty_ratio;
 	int ret;
···
 }
 
 int dirty_bytes_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *lenp,
-		loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned long old_bytes = vm_dirty_bytes;
 	int ret;
···
  * sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
  */
 int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	unsigned int old_interval = dirty_writeback_interval;
 	int ret;

mm/page_alloc.c

···
  * sysctl handler for numa_zonelist_order
  */
 int numa_zonelist_order_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *length,
-		loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
-	char *str;
-	int ret;
-
-	if (!write)
-		return proc_dostring(table, write, buffer, length, ppos);
-	str = memdup_user_nul(buffer, 16);
-	if (IS_ERR(str))
-		return PTR_ERR(str);
-
-	ret = __parse_numa_zonelist_order(str);
-	kfree(str);
-	return ret;
+	if (write)
+		return __parse_numa_zonelist_order(buffer);
+	return proc_dostring(table, write, buffer, length, ppos);
 }
 
 
···
  *	changes.
  */
 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
 
···
 }
 
 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
 
···
 
 
 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
 
···
 }
 
 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	int rc;
 
···
  * if in function of the boot time zone sizes.
  */
 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	proc_dointvec_minmax(table, write, buffer, length, ppos);
 	setup_per_zone_lowmem_reserve();
···
  * pagelist can have before it gets flushed back to buddy allocator.
  */
 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
-	void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	struct zone *zone;
 	int old_percpu_pagelist_fraction;

mm/util.c

···
 unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
 unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
 
-int overcommit_ratio_handler(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp,
-			     loff_t *ppos)
+int overcommit_ratio_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	int ret;
 
···
 	return ret;
 }
 
-int overcommit_kbytes_handler(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp,
-			     loff_t *ppos)
+int overcommit_kbytes_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	int ret;
 

mm/vmstat.c

···
 static DEFINE_MUTEX(vm_numa_stat_lock);
 
 int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
-		void __user *buffer, size_t *length, loff_t *ppos)
+		void *buffer, size_t *length, loff_t *ppos)
 {
 	int ret, oldval;
 
···
 }
 
 int vmstat_refresh(struct ctl_table *table, int write,
-		   void __user *buffer, size_t *lenp, loff_t *ppos)
+		   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	long val;
 	int err;

net/bridge/br_netfilter_hooks.c

···
 #ifdef CONFIG_SYSCTL
 static
 int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
-			    void __user *buffer, size_t *lenp, loff_t *ppos)
+			    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 

net/core/neighbour.c

···
 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
 
 static int proc_unres_qlen(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int size, ret;
 	struct ctl_table tmp = *ctl;
···
 }
 
 static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
-					   void __user *buffer,
-					   size_t *lenp, loff_t *ppos)
+					   void *buffer, size_t *lenp,
+					   loff_t *ppos)
 {
 	struct ctl_table tmp = *ctl;
 	int ret;
···
 	return ret;
 }
 
-int neigh_proc_dointvec(struct ctl_table *ctl, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+int neigh_proc_dointvec(struct ctl_table *ctl, int write, void *buffer,
+			size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
 
···
 }
 EXPORT_SYMBOL(neigh_proc_dointvec);
 
-int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
-				void __user *buffer,
+int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, void *buffer,
 				size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
···
 EXPORT_SYMBOL(neigh_proc_dointvec_jiffies);
 
 static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
-					      void __user *buffer,
-					      size_t *lenp, loff_t *ppos)
+					      void *buffer, size_t *lenp,
+					      loff_t *ppos)
 {
 	int ret = proc_dointvec_userhz_jiffies(ctl, write, buffer, lenp, ppos);
 
···
 }
 
 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
-				   void __user *buffer,
-				   size_t *lenp, loff_t *ppos)
+				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
 
···
 EXPORT_SYMBOL(neigh_proc_dointvec_ms_jiffies);
 
 static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
-					  void __user *buffer,
-					  size_t *lenp, loff_t *ppos)
+					  void *buffer, size_t *lenp,
+					  loff_t *ppos)
 {
 	int ret = proc_unres_qlen(ctl, write, buffer, lenp, ppos);
 
···
 }
 
 static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
-					  void __user *buffer,
-					  size_t *lenp, loff_t *ppos)
+					  void *buffer, size_t *lenp,
+					  loff_t *ppos)
 {
 	struct neigh_parms *p = ctl->extra2;
 	int ret;

net/core/sysctl_net_core.c

···
 
 #ifdef CONFIG_RPS
 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned int orig_size, size;
 	int ret, i;
···
 static DEFINE_MUTEX(flow_limit_update_mutex);
 
 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct sd_flow_limit *cur;
 	struct softnet_data *sd;
···
 		}
 		if (len < *lenp)
 			kbuf[len++] = '\n';
-		if (copy_to_user(buffer, kbuf, len)) {
-			ret = -EFAULT;
-			goto done;
-		}
+		memcpy(buffer, kbuf, len);
 		*lenp = len;
 		*ppos += len;
 	}
···
 }
 
 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
-				       void __user *buffer, size_t *lenp,
-				       loff_t *ppos)
+				       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned int old, *ptr;
 	int ret;
···
 
 #ifdef CONFIG_NET_SCHED
 static int set_default_qdisc(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	char id[IFNAMSIZ];
 	struct ctl_table tbl = {
···
 #endif
 
 static int proc_do_dev_weight(struct ctl_table *table, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 
···
 }
 
 static int proc_do_rss_key(struct ctl_table *table, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table fake_table;
 	char buf[NETDEV_RSS_KEY_LEN * 3];
···
 
 #ifdef CONFIG_BPF_JIT
 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
-					   void __user *buffer, size_t *lenp,
+					   void *buffer, size_t *lenp,
 					   loff_t *ppos)
 {
 	int ret, jit_enable = *(int *)table->data;
···
 # ifdef CONFIG_HAVE_EBPF_JIT
 static int
 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
-				    void __user *buffer, size_t *lenp,
-				    loff_t *ppos)
+				    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
···
 
 static int
 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
-				     void __user *buffer, size_t *lenp,
-				     loff_t *ppos)
+				     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;

net/decnet/dn_dev.c

···
 static int min_priority[1];
 static int max_priority[] = { 127 }; /* From DECnet spec */
 
-static int dn_forwarding_proc(struct ctl_table *, int,
-			void __user *, size_t *, loff_t *);
+static int dn_forwarding_proc(struct ctl_table *, int, void *, size_t *,
+		loff_t *);
 static struct dn_dev_sysctl_table {
 	struct ctl_table_header *sysctl_header;
 	struct ctl_table dn_dev_vars[5];
···
 }
 
 static int dn_forwarding_proc(struct ctl_table *table, int write,
-				void __user *buffer,
-				size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 #ifdef CONFIG_DECNET_ROUTER
 	struct net_device *dev = table->extra1;

net/decnet/sysctl_net_decnet.c

···
 }
 
 static int dn_node_address_handler(struct ctl_table *table, int write,
-				void __user *buffer,
-				size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	char addr[DN_ASCBUF_LEN];
 	size_t len;
···
 
 	if (write) {
 		len = (*lenp < DN_ASCBUF_LEN) ? *lenp : (DN_ASCBUF_LEN-1);
-
-		if (copy_from_user(addr, buffer, len))
-			return -EFAULT;
-
+		memcpy(addr, buffer, len);
 		addr[len] = 0;
 		strip_it(addr);
 
···
 	len = strlen(addr);
 	addr[len++] = '\n';
 
-	if (len > *lenp) len = *lenp;
-
-	if (copy_to_user(buffer, addr, len))
-		return -EFAULT;
-
+	if (len > *lenp)
+		len = *lenp;
+	memcpy(buffer, addr, len);
 	*lenp = len;
 	*ppos += len;
 
···
 }
 
 static int dn_def_dev_handler(struct ctl_table *table, int write,
-				void __user *buffer,
-				size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	size_t len;
 	struct net_device *dev;
···
 		if (*lenp > 16)
 			return -E2BIG;
 
-		if (copy_from_user(devname, buffer, *lenp))
-			return -EFAULT;
-
+		memcpy(devname, buffer, *lenp);
 		devname[*lenp] = 0;
 		strip_it(devname);
 
···
 
 	if (len > *lenp) len = *lenp;
 
-	if (copy_to_user(buffer, devname, len))
-		return -EFAULT;
-
+	memcpy(buffer, devname, len);
 	*lenp = len;
 	*ppos += len;
 

net/ipv4/devinet.c

···
 }
 
 static int devinet_conf_proc(struct ctl_table *ctl, int write,
-			     void __user *buffer,
-			     size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int old_value = *(int *)ctl->data;
 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
···
 }
 
 static int devinet_sysctl_forward(struct ctl_table *ctl, int write,
-				  void __user *buffer,
-				  size_t *lenp, loff_t *ppos)
+				  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
···
 }
 
 static int ipv4_doint_and_flush(struct ctl_table *ctl, int write,
-				void __user *buffer,
-				size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;

net/ipv4/route.c

···
 static int ip_min_valid_pmtu __read_mostly	= IPV4_MIN_MTU;
 
 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
-					void __user *buffer,
-					size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = (struct net *)__ctl->extra1;
 

net/ipv4/sysctl_net_ipv4.c

···
 
 /* Validate changes from /proc interface. */
 static int ipv4_local_port_range(struct ctl_table *table, int write,
-				 void __user *buffer,
-				 size_t *lenp, loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net =
 		container_of(table->data, struct net, ipv4.ip_local_ports.range);
···
 
 /* Validate changes from /proc interface. */
 static int ipv4_privileged_ports(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(table->data, struct net,
 	    ipv4.sysctl_ip_prot_sock);
···
 
 /* Validate changes from /proc interface. */
 static int ipv4_ping_group_range(struct ctl_table *table, int write,
-				 void __user *buffer,
-				 size_t *lenp, loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct user_namespace *user_ns = current_user_ns();
 	int ret;
···
 }
 
 static int ipv4_fwd_update_priority(struct ctl_table *table, int write,
-				    void __user *buffer,
-				    size_t *lenp, loff_t *ppos)
+				    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net;
 	int ret;
···
 }
 
 static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
-				       void __user *buffer, size_t *lenp, loff_t *ppos)
+				       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(ctl->data, struct net,
 				       ipv4.tcp_congestion_control);
···
 }
 
 static int proc_tcp_available_congestion_control(struct ctl_table *ctl,
-						 int write,
-						 void __user *buffer, size_t *lenp,
-						 loff_t *ppos)
+						 int write, void *buffer,
+						 size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX, };
 	int ret;
···
 }
 
 static int proc_allowed_congestion_control(struct ctl_table *ctl,
-					   int write,
-					   void __user *buffer, size_t *lenp,
-					   loff_t *ppos)
+					   int write, void *buffer,
+					   size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX };
 	int ret;
···
 }
 
 static int proc_tcp_fastopen_key(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(table->data, struct net,
 	    ipv4.sysctl_tcp_fastopen);
···
 }
 
 static int proc_tcp_early_demux(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = 0;
 
···
 }
 
 static int proc_udp_early_demux(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = 0;
 
···
 }
 
 static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
-					     int write,
-					     void __user *buffer,
+					     int write, void *buffer,
 					     size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(table->data, struct net,
···
 }
 
 static int proc_tcp_available_ulp(struct ctl_table *ctl,
-				  int write,
-				  void __user *buffer, size_t *lenp,
+				  int write, void *buffer, size_t *lenp,
 				  loff_t *ppos)
 {
 	struct ctl_table tbl = { .maxlen = TCP_ULP_BUF_MAX, };
···
 
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 static int proc_fib_multipath_hash_policy(struct ctl_table *table, int write,
-					  void __user *buffer, size_t *lenp,
+					  void *buffer, size_t *lenp,
 					  loff_t *ppos)
 {
 	struct net *net = container_of(table->data, struct net,

net/ipv6/addrconf.c

···
 
 #ifdef CONFIG_SYSCTL
 
-static
-int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
···
 	return ret;
 }
 
-static
-int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct inet6_dev *idev = ctl->extra1;
 	int min_mtu = IPV6_MIN_MTU;
···
 	return 0;
 }
 
-static
-int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
-			    void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
···
 	return ret;
 }
 
-static
-int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int ret;
···
 }
 
 static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
-					 void __user *buffer, size_t *lenp,
+					 void *buffer, size_t *lenp,
 					 loff_t *ppos)
 {
 	int ret = 0;
···
 }
 
 static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
-					 void __user *buffer, size_t *lenp,
+					 void *buffer, size_t *lenp,
 					 loff_t *ppos)
 {
 	int err;
···
 
 static
 int addrconf_sysctl_ignore_routes_with_linkdown(struct ctl_table *ctl,
-						int write,
-						void __user *buffer,
+						int write, void *buffer,
 						size_t *lenp,
 						loff_t *ppos)
 {
···
 	return 0;
 }
 
-static
-int addrconf_sysctl_disable_policy(struct ctl_table *ctl, int write,
-				   void __user *buffer, size_t *lenp,
-				   loff_t *ppos)
+static int addrconf_sysctl_disable_policy(struct ctl_table *ctl, int write,
+				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;

net/ipv6/ndisc.c

···
 	}
 }
 
-int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void __user *buffer, size_t *lenp, loff_t *ppos)
+int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	struct net_device *dev = ctl->extra1;
 	struct inet6_dev *idev;

net/ipv6/route.c

···
 
 #ifdef CONFIG_SYSCTL
 
-static
-int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+static int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
+			      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net;
 	int delay;

net/ipv6/sysctl_net_ipv6.c

···
 static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
 
 static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,
-					  void __user *buffer, size_t *lenp,
-					  loff_t *ppos)
+					  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net;
 	int ret;

net/mpls/af_mpls.c

···
 	(&((struct mpls_dev *)0)->field)
 
 static int mpls_conf_proc(struct ctl_table *ctl, int write,
-			  void __user *buffer,
-			  size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int oval = *(int *)ctl->data;
 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
···
 }
 
 static int mpls_platform_labels(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = table->data;
 	int platform_labels = net->mpls.platform_labels;

net/netfilter/ipvs/ip_vs_ctl.c

···
 
 static int
 proc_do_defense_mode(struct ctl_table *table, int write,
-		     void __user *buffer, size_t *lenp, loff_t *ppos)
+		     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct netns_ipvs *ipvs = table->extra2;
 	int *valp = table->data;
···
 
 static int
 proc_do_sync_threshold(struct ctl_table *table, int write,
-		       void __user *buffer, size_t *lenp, loff_t *ppos)
+		       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = table->data;
 	int val[2];
···
 
 static int
 proc_do_sync_ports(struct ctl_table *table, int write,
-		   void __user *buffer, size_t *lenp, loff_t *ppos)
+		   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = table->data;
 	int val = *valp;

net/netfilter/nf_conntrack_standalone.c

···
 
 static int
 nf_conntrack_hash_sysctl(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 

net/netfilter/nf_log.c

···
 };
 
 static int nf_log_proc_dostring(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	const struct nf_logger *logger;
 	char buf[NFLOGGER_NAME_LEN];

net/phonet/sysctl.c

···
 }
 
 static int proc_local_port_range(struct ctl_table *table, int write,
-				void __user *buffer,
-				size_t *lenp, loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 	int range[2] = {local_port_range[0], local_port_range[1]};

net/rds/tcp.c

···
 static struct kmem_cache *rds_tcp_conn_slab;
 
 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *fpos);
+				 void *buffer, size_t *lenp, loff_t *fpos);
 
 static int rds_tcp_min_sndbuf = SOCK_MIN_SNDBUF;
 static int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;
···
 }
 
 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *fpos)
+				 void *buffer, size_t *lenp, loff_t *fpos)
 {
 	struct net *net = current->nsproxy->net_ns;
 	int err;

net/sctp/sysctl.c

···
 	? UINT_MAX : MAX_SCHEDULE_TIMEOUT / HZ;
 
 static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos);
+				 void *buffer, size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos);
-static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos);
+				void *buffer, size_t *lenp, loff_t *ppos);
+static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write, void *buffer,
+				size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
-				   void __user *buffer, size_t *lenp,
-				   loff_t *ppos);
+				   void *buffer, size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
-			     void __user *buffer, size_t *lenp,
-			     loff_t *ppos);
+			     void *buffer, size_t *lenp, loff_t *ppos);
 
 static struct ctl_table sctp_table[] = {
 	{
···
 };
 
 static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = current->nsproxy->net_ns;
 	struct ctl_table tbl;
···
 }
 
 static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = current->nsproxy->net_ns;
 	unsigned int min = *(unsigned int *) ctl->extra1;
···
 }
 
 static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = current->nsproxy->net_ns;
 	unsigned int min = *(unsigned int *) ctl->extra1;
···
 }
 
 static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
-				   void __user *buffer, size_t *lenp,
-				   loff_t *ppos)
+				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (write)
 		pr_warn_once("Changing rto_alpha or rto_beta may lead to "
···
 }
 
 static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
-			     void __user *buffer, size_t *lenp,
-			     loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = current->nsproxy->net_ns;
 	struct ctl_table tbl;

net/sunrpc/sysctl.c

···
 }
 
 static int proc_do_xprt(struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+			void *buffer, size_t *lenp, loff_t *ppos)
 {
 	char tmpbuf[256];
 	size_t len;
···
 		return 0;
 	}
 	len = svc_print_xprts(tmpbuf, sizeof(tmpbuf));
-	return simple_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);
+	return memory_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);
 }
 
 static int
-proc_dodebug(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+proc_dodebug(struct ctl_table *table, int write, void *buffer, size_t *lenp,
+	     loff_t *ppos)
 {
-	char		tmpbuf[20], c, *s = NULL;
-	char __user *p;
+	char		tmpbuf[20], *s = NULL;
+	char *p;
 	unsigned int	value;
 	size_t		left, len;
 
···
 	left = *lenp;
 
 	if (write) {
-		if (!access_ok(buffer, left))
-			return -EFAULT;
 		p = buffer;
-		while (left && __get_user(c, p) >= 0 && isspace(c))
-			left--, p++;
+		while (left && isspace(*p)) {
+			left--;
+			p++;
+		}
 		if (!left)
 			goto done;
 
 		if (left > sizeof(tmpbuf) - 1)
 			return -EINVAL;
-		if (copy_from_user(tmpbuf, p, left))
-			return -EFAULT;
+		memcpy(tmpbuf, p, left);
 		tmpbuf[left] = '\0';
 
 		value = simple_strtol(tmpbuf, &s, 0);
···
 		len = sprintf(tmpbuf, "0x%04x", *(unsigned int *) table->data);
 		if (len > left)
 			len = left;
-		if (copy_to_user(buffer, tmpbuf, len))
-			return -EFAULT;
+		memcpy(buffer, tmpbuf, len);
 		if ((left -= len) > 0) {
-			if (put_user('\n', (char __user *)buffer + len))
-				return -EFAULT;
+			*((char *)buffer + len) = '\n';
 			left--;
 		}
 	}

net/sunrpc/xprtrdma/svc_rdma.c

···
  * current value.
  */
 static int read_reset_stat(struct ctl_table *table, int write,
-			   void __user *buffer, size_t *lenp,
-			   loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	atomic_t *stat = (atomic_t *)table->data;
 
···
 		len -= *ppos;
 		if (len > *lenp)
 			len = *lenp;
-		if (len && copy_to_user(buffer, str_buf, len))
-			return -EFAULT;
+		if (len)
+			memcpy(buffer, str_buf, len);
 		*lenp = len;
 		*ppos += len;
 	}

security/apparmor/lsm.c

···
 
 #ifdef CONFIG_SYSCTL
 static int apparmor_dointvec(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!policy_admin_capable(NULL))
 		return -EPERM;

security/min_addr.c

···
  * calls update_mmap_min_addr() so non MAP_FIXED hints get rounded properly
  */
 int mmap_min_addr_handler(struct ctl_table *table, int write,
-			  void __user *buffer, size_t *lenp, loff_t *ppos)
+			  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret;
 

security/yama/yama_lsm.c

···
 
 #ifdef CONFIG_SYSCTL
 static int yama_dointvec_minmax(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table table_copy;