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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240// SPDX-License-Identifier: GPL-2.0// error-inject.c: Function-level error injection table#include <linux/error-injection.h>#include <linux/debugfs.h>#include <linux/kallsyms.h>#include <linux/kprobes.h>#include <linux/module.h>#include <linux/mutex.h>#include <linux/list.h>#include <linux/slab.h>#include <asm/sections.h>
/* Whitelist of symbols that can be overridden for error injection. */static LIST_HEAD(error_injection_list);static DEFINE_MUTEX(ei_mutex);struct ei_entry { struct list_head list; unsigned long start_addr; unsigned long end_addr; int etype; void *priv;};
bool within_error_injection_list(unsigned long addr){ struct ei_entry *ent; bool ret = false;
mutex_lock(&ei_mutex); list_for_each_entry(ent, &error_injection_list, list) { if (addr >= ent->start_addr && addr < ent->end_addr) { ret = true; break; } } mutex_unlock(&ei_mutex); return ret;}
int get_injectable_error_type(unsigned long addr){ struct ei_entry *ent; int ei_type = -EINVAL;
mutex_lock(&ei_mutex); list_for_each_entry(ent, &error_injection_list, list) { if (addr >= ent->start_addr && addr < ent->end_addr) { ei_type = ent->etype; break; } } mutex_unlock(&ei_mutex);
return ei_type;}
/* * Lookup and populate the error_injection_list. * * For safety reasons we only allow certain functions to be overridden with * bpf_error_injection, so we need to populate the list of the symbols that have * been marked as safe for overriding. */static void populate_error_injection_list(struct error_injection_entry *start, struct error_injection_entry *end, void *priv){ struct error_injection_entry *iter; struct ei_entry *ent; unsigned long entry, offset = 0, size = 0;
mutex_lock(&ei_mutex); for (iter = start; iter < end; iter++) { entry = (unsigned long)dereference_symbol_descriptor((void *)iter->addr);
if (!kernel_text_address(entry) || !kallsyms_lookup_size_offset(entry, &size, &offset)) { pr_err("Failed to find error inject entry at %p\n", (void *)entry); continue; }
ent = kmalloc_obj(*ent); if (!ent) break; ent->start_addr = entry; ent->end_addr = entry + size; ent->etype = iter->etype; ent->priv = priv; INIT_LIST_HEAD(&ent->list); list_add_tail(&ent->list, &error_injection_list); } mutex_unlock(&ei_mutex);}
/* Markers of the _error_inject_whitelist section */extern struct error_injection_entry __start_error_injection_whitelist[];extern struct error_injection_entry __stop_error_injection_whitelist[];
static void __init populate_kernel_ei_list(void){ populate_error_injection_list(__start_error_injection_whitelist, __stop_error_injection_whitelist, NULL);}
#ifdef CONFIG_MODULESstatic void module_load_ei_list(struct module *mod){ if (!mod->num_ei_funcs) return;
populate_error_injection_list(mod->ei_funcs, mod->ei_funcs + mod->num_ei_funcs, mod);}
static void module_unload_ei_list(struct module *mod){ struct ei_entry *ent, *n;
if (!mod->num_ei_funcs) return;
mutex_lock(&ei_mutex); list_for_each_entry_safe(ent, n, &error_injection_list, list) { if (ent->priv == mod) { list_del_init(&ent->list); kfree(ent); } } mutex_unlock(&ei_mutex);}
/* Module notifier call back, checking error injection table on the module */static int ei_module_callback(struct notifier_block *nb, unsigned long val, void *data){ struct module *mod = data;
if (val == MODULE_STATE_COMING) module_load_ei_list(mod); else if (val == MODULE_STATE_GOING) module_unload_ei_list(mod);
return NOTIFY_DONE;}
static struct notifier_block ei_module_nb = { .notifier_call = ei_module_callback, .priority = 0};
static __init int module_ei_init(void){ return register_module_notifier(&ei_module_nb);}#else /* !CONFIG_MODULES */#define module_ei_init() (0)#endif
/* * error_injection/whitelist -- shows which functions can be overridden for * error injection. */static void *ei_seq_start(struct seq_file *m, loff_t *pos){ mutex_lock(&ei_mutex); return seq_list_start(&error_injection_list, *pos);}
static void ei_seq_stop(struct seq_file *m, void *v){ mutex_unlock(&ei_mutex);}
static void *ei_seq_next(struct seq_file *m, void *v, loff_t *pos){ return seq_list_next(v, &error_injection_list, pos);}
static const char *error_type_string(int etype){ switch (etype) { case EI_ETYPE_NULL: return "NULL"; case EI_ETYPE_ERRNO: return "ERRNO"; case EI_ETYPE_ERRNO_NULL: return "ERRNO_NULL"; case EI_ETYPE_TRUE: return "TRUE"; default: return "(unknown)"; }}
static int ei_seq_show(struct seq_file *m, void *v){ struct ei_entry *ent = list_entry(v, struct ei_entry, list);
seq_printf(m, "%ps\t%s\n", (void *)ent->start_addr, error_type_string(ent->etype)); return 0;}
static const struct seq_operations ei_sops = { .start = ei_seq_start, .next = ei_seq_next, .stop = ei_seq_stop, .show = ei_seq_show,};
DEFINE_SEQ_ATTRIBUTE(ei);
static int __init ei_debugfs_init(void){ struct dentry *dir, *file;
dir = debugfs_create_dir("error_injection", NULL);
file = debugfs_create_file("list", 0444, dir, NULL, &ei_fops); if (IS_ERR(file)) { debugfs_remove(dir); return PTR_ERR(file); }
return 0;}
static int __init init_error_injection(void){ populate_kernel_ei_list();
if (!module_ei_init()) ei_debugfs_init();
return 0;}late_initcall(init_error_injection);