Messages in this thread | | | Date | Fri, 06 Aug 2021 17:22:55 +0200 | From | "Hannes Frederic Sowa" <> | Subject | Re: [PATCH v2] once: Fix panic when module unload |
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On Fri, Aug 6, 2021, at 10:21, Kefeng Wang wrote: > 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>
Thanks, Hannes
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