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authorTetsuo Handa2022-07-20 23:47:55 +0900
committerakpm2022-07-29 18:07:13 -0700
commit14773bfa70e67f4d4ebd60e60cb6e25e8c84d4c0 (patch)
tree67152cd43719fd51e7975bf56bf1194bafbfa181 /mm/vmscan.c
parent187e7c41445a0f202bb551f08ca7f8158fea1cd7 (diff)
mm: shrinkers: fix double kfree on shrinker name
syzbot is reporting double kfree() at free_prealloced_shrinker() [1], for destroy_unused_super() calls free_prealloced_shrinker() even if prealloc_shrinker() returned an error. Explicitly clear shrinker name when prealloc_shrinker() called kfree(). [roman.gushchin@linux.dev: zero shrinker->name in all cases where shrinker->name is freed] Link: https://lkml.kernel.org/r/YtgteTnQTgyuKUSY@castle Link: https://syzkaller.appspot.com/bug?extid=8b481578352d4637f510 [1] Link: https://lkml.kernel.org/r/ffa62ece-6a42-2644-16cf-0d33ef32c676@I-love.SAKURA.ne.jp Fixes: e33c267ab70de424 ("mm: shrinkers: provide shrinkers with names") Reported-by: syzbot <syzbot+8b481578352d4637f510@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f58761cea0a0..fbb4108250ee 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -644,8 +644,10 @@ int prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...)
return -ENOMEM;
err = __prealloc_shrinker(shrinker);
- if (err)
+ if (err) {
kfree_const(shrinker->name);
+ shrinker->name = NULL;
+ }
return err;
}
@@ -660,6 +662,7 @@ void free_prealloced_shrinker(struct shrinker *shrinker)
{
#ifdef CONFIG_SHRINKER_DEBUG
kfree_const(shrinker->name);
+ shrinker->name = NULL;
#endif
if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
down_write(&shrinker_rwsem);
@@ -704,8 +707,10 @@ int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
return -ENOMEM;
err = __register_shrinker(shrinker);
- if (err)
+ if (err) {
kfree_const(shrinker->name);
+ shrinker->name = NULL;
+ }
return err;
}
#else