diff options
| -rw-r--r-- | kernel/module.c | 5 | ||||
| -rw-r--r-- | lib/bug.c | 20 |
2 files changed, 17 insertions, 8 deletions
diff --git a/kernel/module.c b/kernel/module.c index bed608b8c8a6..d596a306b0a1 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1850,9 +1850,10 @@ static void free_module(struct module *mod) mutex_lock(&module_mutex); /* Unlink carefully: kallsyms could be walking list. */ list_del_rcu(&mod->list); - /* Wait for RCU synchronizing before releasing mod->list. */ - synchronize_rcu(); + /* Remove this module from bug list, this uses list_del_rcu */ module_bug_cleanup(mod); + /* Wait for RCU synchronizing before releasing mod->list and buglist. */ + synchronize_rcu(); mutex_unlock(&module_mutex); /* This may be NULL, but that's OK */ diff --git a/lib/bug.c b/lib/bug.c index d1d7c7878900..0c3bd9552b6f 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -64,16 +64,22 @@ static LIST_HEAD(module_bug_list); static const struct bug_entry *module_find_bug(unsigned long bugaddr) { struct module *mod; + const struct bug_entry *bug = NULL; - list_for_each_entry(mod, &module_bug_list, bug_list) { - const struct bug_entry *bug = mod->bug_table; + rcu_read_lock(); + list_for_each_entry_rcu(mod, &module_bug_list, bug_list) { unsigned i; + bug = mod->bug_table; for (i = 0; i < mod->num_bugs; ++i, ++bug) if (bugaddr == bug_addr(bug)) - return bug; + goto out; } - return NULL; + bug = NULL; +out: + rcu_read_unlock(); + + return bug; } void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, @@ -99,13 +105,15 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, * Strictly speaking this should have a spinlock to protect against * traversals, but since we only traverse on BUG()s, a spinlock * could potentially lead to deadlock and thus be counter-productive. + * Thus, this uses RCU to safely manipulate the bug list, since BUG + * must run in non-interruptive state. */ - list_add(&mod->bug_list, &module_bug_list); + list_add_rcu(&mod->bug_list, &module_bug_list); } void module_bug_cleanup(struct module *mod) { - list_del(&mod->bug_list); + list_del_rcu(&mod->bug_list); } #else |