The patch titled
Subject: mm: shrinkers: fix double kfree on shrinker name
has been added to the -mm mm-unstable branch. Its filename is
mm-shrinkers-fix-double-kfree-on-shrinker-name.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shrinkers-fix-double-kfree-on-shrinker-name.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Subject: mm: shrinkers: fix double kfree on shrinker name
Date: Wed, 20 Jul 2022 23:47:55 +0900
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().
Link: https://syzkaller.appspot.com/bug?extid=8b481578352d4637f510 [1]
Link: https://lkml.kernel.org/r/ffa62ece-6a42-2644-16cf-0d33ef32c676@xxxxxxxxxxxxxxxxxxx
Fixes: e33c267ab70de424 ("mm: shrinkers: provide shrinkers with names")
Reported-by: syzbot <syzbot+8b481578352d4637f510@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/vmscan.c~mm-shrinkers-fix-double-kfree-on-shrinker-name
+++ a/mm/vmscan.c
@@ -704,8 +704,10 @@ int register_shrinker(struct shrinker *s
return -ENOMEM;
err = __register_shrinker(shrinker);
- if (err)
+ if (err) {
kfree_const(shrinker->name);
+ shrinker->name = NULL;
+ }
return err;
}
#else
_
Patches currently in -mm which might be from penguin-kernel@xxxxxxxxxxxxxxxxxxx are
mm-shrinkers-fix-double-kfree-on-shrinker-name.patch
