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From: Lilitha Persefoni Gkini <lilithpgkini@gmail.com>
To: Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Hyeonggon Yoo <42.hyeyoo@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH] slub: Fix Off-By-One in the While condition in on_freelist()
Date: Sat, 15 Feb 2025 18:57:01 +0200	[thread overview]
Message-ID: <Z7DHXVNJ5aVBM2WA@Arch> (raw)

The condition `nr <= slab->objects` in the `on_freelist()` serves as
bound while walking through the `freelist` linked list because we can't
have more free objects than the maximum amount of objects in the slab.
But the `=` can result in an extra unnecessary iteration.

The patch changes it to `nr < slab->objects` to ensure it iterates
at most `slab->objects` number of times.

Signed-off-by: Lilitha Persefoni Gkini <lilithpgkini@gmail.com>
---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index 1f50129dcfb3..ad42450d4b0f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1435,7 +1435,7 @@ static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
 	int max_objects;
 
 	fp = slab->freelist;
-	while (fp && nr <= slab->objects) {
+	while (fp && nr < slab->objects) {
 		if (fp == search)
 			return 1;
 		if (!check_valid_pointer(s, slab, fp)) {
-- 
2.48.1



             reply	other threads:[~2025-02-15 16:57 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-15 16:57 Lilitha Persefoni Gkini [this message]
2025-02-20  8:20 ` Harry Yoo
2025-02-20  9:21   ` Harry Yoo
2025-02-21 14:57     ` Lilith Gkini
2025-02-22  3:58       ` Harry Yoo
2025-02-22  9:24         ` Lilith Gkini
2025-02-24  0:00           ` Harry Yoo
2025-02-24 12:12             ` Lilith Gkini
2025-02-25 10:08               ` Harry Yoo
2025-02-27 16:40                 ` Lilith Gkini
2025-03-02 13:11                   ` Harry Yoo
2025-03-02 18:01 Lilith Persefoni Gkini
2025-03-03 11:06 ` Vlastimil Babka
2025-03-03 16:41   ` Lilith Gkini
2025-03-03 17:39     ` Christoph Lameter (Ampere)
2025-03-03 19:06     ` Vlastimil Babka
2025-03-04  8:24       ` Lilith Gkini
2025-03-04  8:41         ` Vlastimil Babka
2025-03-04 11:06           ` Lilith Gkini
2025-03-04 11:20             ` Vlastimil Babka
2025-03-04 12:18               ` Lilith Gkini
2025-03-04 14:25                 ` Vlastimil Babka
2025-03-04 17:14                   ` Lilith Gkini

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