Merge tag 'mac80211-for-davem-2015-01-06' of git://git.kernel.org/pub/scm/linux/kerne...

[cascardo/linux.git] / lib / bug.c

diff --git a/lib/bug.c b/lib/bug.c
index d1d7c78..0c3bd95 100644 (file)
--- 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