[merged mm-stable] mm-shrinker-fix-refcount-leak-in-shrink_slab_memcg.patch removed from -mm tree

[merged mm-stable] mm-shrinker-fix-refcount-leak-in-shrink_slab_memcg.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/shrinker: fix refcount leak in shrink_slab_memcg()
has been removed from the -mm tree.  Its filename was
     mm-shrinker-fix-refcount-leak-in-shrink_slab_memcg.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Altan Hacigumus <ahacigu.linux@gmail.com>
Subject: mm/shrinker: fix refcount leak in shrink_slab_memcg()
Date: Tue, 3 Feb 2026 19:35:53 -0800

When kmem is disabled for memcg, slab-backed shrinkers are skipped. 
However, shrink_slab_memcg() doesn't drop the reference acquired via
shrinker_try_get() before continuing.

Add the missing shrinker_put().

Also, since memcg_kmem_online() and shrinker flags cannot change
dynamically, remove the shrinker from the bitmap to avoid unnecessary
future scans.

Link: https://lkml.kernel.org/r/20260204033553.50039-1-ahacigu.linux@gmail.com
Fixes: 50d09da8e119 ("mm: shrinker: make memcg slab shrink lockless")
Signed-off-by: Altan Hacigumus <ahacigu.linux@gmail.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
  Link: https://lore.kernel.org/r/20260203073757.135088-1-ahacigu.linux@gmail.com
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/shrinker.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/shrinker.c~mm-shrinker-fix-refcount-leak-in-shrink_slab_memcg
+++ a/mm/shrinker.c
@@ -544,8 +544,11 @@ again:
 
 			/* Call non-slab shrinkers even though kmem is disabled */
 			if (!memcg_kmem_online() &&
-			    !(shrinker->flags & SHRINKER_NONSLAB))
+			    !(shrinker->flags & SHRINKER_NONSLAB)) {
+				clear_bit(offset, unit->map);
+				shrinker_put(shrinker);
 				continue;
+			}
 
 			ret = do_shrink_slab(&sc, shrinker, priority);
 			if (ret == SHRINK_EMPTY) {
_

Patches currently in -mm which might be from ahacigu.linux@gmail.com are