From: Roman Gushchin <roman.gushchin@linux.dev>
Date: Wed, 20 Jul 2022 16:29:45 +0000 (-0700)
Subject: mm-shrinkers-fix-double-kfree-on-shrinker-name-fix
X-Git-Tag: howlett/maple/20220722_2~148
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=90b5a54c4ccb33799f1cd4d3de37761d55646ea4;p=users%2Fjedix%2Flinux-maple.git

mm-shrinkers-fix-double-kfree-on-shrinker-name-fix

zero shrinker->name in all cases where shrinker->name is freed

Link: https://lkml.kernel.org/r/YtgteTnQTgyuKUSY@castle
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c
index e5b40c43221d0..b05295bab3222 100644
--- a/mm/shrinker_debug.c
+++ b/mm/shrinker_debug.c
@@ -251,6 +251,7 @@ void shrinker_debugfs_remove(struct shrinker *shrinker)
 	lockdep_assert_held(&shrinker_rwsem);
 
 	kfree_const(shrinker->name);
+	shrinker->name = NULL;
 
 	if (!shrinker->debugfs_entry)
 		return;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f8d97b905f210..fbb4108250ee4 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);