On Sat 16-12-17 22:29:37, Aliaksei Karaliou wrote: > unregister_shrinker() does not have any sanitizing inside so > calling it twice will oops because of double free attempt or so. > This patch makes unregister_shrinker() safer and allows calling > it on resource freeing path without explicit knowledge of whether > shrinker was successfully registered or not. Tetsuo has made it half way to this already [1]. So maybe we should fold shrinker->nr_deferred = NULL to his patch and finally merge it. [1] http://lkml.kernel.org/r/1511523385-6433-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx > > Signed-off-by: Aliaksei Karaliou <akaraliou.dev@xxxxxxxxx> > --- > mm/vmscan.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 65c4fa26abfa..7cb56db5e9ca 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -281,10 +281,14 @@ EXPORT_SYMBOL(register_shrinker); > */ > void unregister_shrinker(struct shrinker *shrinker) > { > + if (!shrinker->nr_deferred) > + return; > + > down_write(&shrinker_rwsem); > list_del(&shrinker->list); > up_write(&shrinker_rwsem); > kfree(shrinker->nr_deferred); > + shrinker->nr_deferred = NULL; > } > EXPORT_SYMBOL(unregister_shrinker); > > -- > 2.11.0 > -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
