linux-kernel - [PATCH RT] mm/slub: close possible memory-leak in kmem_cache_alloc

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Date:   Wed, 13 Dec 2017 15:05:55 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-rt-users@...r.kernel.org,
        Jesper Dangaard Brouer <brouer@...hat.com>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Vladimir Davydov <vdavydov@...tuozzo.com>, linux-mm@...ck.org
Subject: [PATCH RT] mm/slub: close possible memory-leak in
 kmem_cache_alloc_bulk()

Under certain circumstances we could leak elements which were moved to
the local "to_free" list. The damage is limited since I can't find any
users here.

Cc: stable-rt@...r.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
Jesper: There are no users of kmem_cache_alloc_bulk() and kfree_bulk().
Only kmem_cache_free_bulk() is used since it was introduced. Do you
think that it would make sense to remove those?

 mm/slub.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/slub.c b/mm/slub.c
index ffd2fa0f415e..9053e929ce9d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3240,6 +3240,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 	return i;
 error:
 	local_irq_enable();
+	free_delayed(&to_free);
 	slab_post_alloc_hook(s, flags, i, p);
 	__kmem_cache_free_bulk(s, i, p);
 	return 0;
-- 
2.15.1