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authorKefeng Wang <wangkefeng.wang@huawei.com>2021-08-06 11:21:24 +0300
committerDavid S. Miller <davem@davemloft.net>2021-08-08 15:00:20 +0300
commit1027b96ec9d34f9abab69bc1a4dc5b1ad8ab1349 (patch)
treecd0aaca19f2c451ac22683a7bfd1d321b915f25d /include/linux/once.h
parentd329e41a08f37c478159d5c3379a17b9c07befa3 (diff)
downloadlinux-1027b96ec9d34f9abab69bc1a4dc5b1ad8ab1349.tar.xz
once: Fix panic when module unload
DO_ONCE DEFINE_STATIC_KEY_TRUE(___once_key); __do_once_done once_disable_jump(once_key); INIT_WORK(&w->work, once_deferred); struct once_work *w; w->key = key; schedule_work(&w->work); module unload //*the key is destroy* process_one_work once_deferred BUG_ON(!static_key_enabled(work->key)); static_key_count((struct static_key *)x) //*access key, crash* When module uses DO_ONCE mechanism, it could crash due to the above concurrency problem, we could reproduce it with link[1]. Fix it by add/put module refcount in the once work process. [1] https://lore.kernel.org/netdev/eaa6c371-465e-57eb-6be9-f4b16b9d7cbf@huawei.com/ Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Reported-by: Minmin chen <chenmingmin@huawei.com> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/once.h')
-rw-r--r--include/linux/once.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/once.h b/include/linux/once.h
index 9225ee6d96c7..ae6f4eb41cbe 100644
--- a/include/linux/once.h
+++ b/include/linux/once.h
@@ -7,7 +7,7 @@
bool __do_once_start(bool *done, unsigned long *flags);
void __do_once_done(bool *done, struct static_key_true *once_key,
- unsigned long *flags);
+ unsigned long *flags, struct module *mod);
/* Call a function exactly once. The idea of DO_ONCE() is to perform
* a function call such as initialization of random seeds, etc, only
@@ -46,7 +46,7 @@ void __do_once_done(bool *done, struct static_key_true *once_key,
if (unlikely(___ret)) { \
func(__VA_ARGS__); \
__do_once_done(&___done, &___once_key, \
- &___flags); \
+ &___flags, THIS_MODULE); \
} \
} \
___ret; \