Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML fixes from Richard Weinberger:
"Four fixes, all discovered by Trinity"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: segv: Save regs only in case of a kernel mode fault
um: Fix hung task in fix_range_common()
um: Ensure that a stub page cannot get unmapped
Revert "um: Fix wait_stub_done() error handling"

arch/um/kernel/tlb.c

···
 #include <mem_user.h>
 #include <os.h>
 #include <skas.h>
+#include <kern_util.h>
 
 struct host_vm_change {
 	struct host_vm_op {
···
 {
 	struct host_vm_op *last;
 	int ret = 0;
+
+	if ((addr >= STUB_START) && (addr < STUB_END))
+		return -EINVAL;
 
 	if (hvc->index != 0) {
 		last = &hvc->ops[hvc->index - 1];
···
 	/* This is not an else because ret is modified above */
 	if (ret) {
 		printk(KERN_ERR "fix_range_common: failed, killing current "
-		       "process\n");
+		       "process: %d\n", task_tgid_vnr(current));
+		/* We are under mmap_sem, release it such that current can terminate */
+		up_write(&current->mm->mmap_sem);
 		force_sig(SIGKILL, current);
+		do_signal();
 	}
 }
 

arch/um/kernel/trap.c

···
 	int is_write = FAULT_WRITE(fi);
 	unsigned long address = FAULT_ADDRESS(fi);
 
-	if (regs)
+	if (!is_user && regs)
 		current->thread.segv_regs = container_of(regs, struct pt_regs, regs);
 
 	if (!is_user && (address >= start_vm) && (address < end_vm)) {

arch/um/os-Linux/skas/process.c

···
 
 void wait_stub_done(int pid)
 {
-	int n, status, err, bad_stop = 0;
+	int n, status, err;
 
 	while (1) {
 		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
···
 
 	if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
 		return;
-	else
-		bad_stop = 1;
 
 bad_wait:
 	err = ptrace_dump_regs(pid);
···
 	printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
 	       "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
 	       status);
-	if (bad_stop)
-		kill(pid, SIGKILL);
-	else
-		fatal_sigsegv();
+	fatal_sigsegv();
 }
 
 extern unsigned long current_stub_stack(void);