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-rw-r--r--kernel/module.c5
-rw-r--r--lib/bug.c20
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