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From: Vlastimil Babka <vbabka@suse.cz>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Harry Yoo <harry.yoo@oracle.com>,
	Christoph Lameter <cl@gentwo.org>,
	 David Rientjes <rientjes@google.com>,
	 Roman Gushchin <roman.gushchin@linux.dev>,
	 Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org,  linux-kernel@vger.kernel.org,
	Vlastimil Babka <vbabka@suse.cz>
Subject: [PATCH v2 1/6] slab: Remove dead code in free_consistency_checks()
Date: Mon, 15 Sep 2025 15:55:08 +0200	[thread overview]
Message-ID: <20250915-slub-slab-validation-v2-1-314690fc1532@suse.cz> (raw)
In-Reply-To: <20250915-slub-slab-validation-v2-0-314690fc1532@suse.cz>

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

We already know that slab is a valid slab as that's checked by the
caller.  In the future, we won't be able to get to a slab pointer
from a non-slab page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 3062f56bf49882538ba5af407de9f69c451f2e29..56143bfd1ae319d384981c810a5ed84af00f4afa 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1684,10 +1684,7 @@ static inline int free_consistency_checks(struct kmem_cache *s,
 		return 0;
 
 	if (unlikely(s != slab->slab_cache)) {
-		if (!folio_test_slab(slab_folio(slab))) {
-			slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
-				 object);
-		} else if (!slab->slab_cache) {
+		if (!slab->slab_cache) {
 			slab_err(NULL, slab, "No slab cache for object 0x%p",
 				 object);
 		} else {

-- 
2.51.0



  reply	other threads:[~2025-09-15 13:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-15 13:55 [PATCH v2 0/6] slab: struct slab pointer validation improvements Vlastimil Babka
2025-09-15 13:55 ` Vlastimil Babka [this message]
2025-09-15 13:55 ` [PATCH v2 2/6] slab: wrap debug slab validation in validate_slab_ptr() Vlastimil Babka
2025-09-15 13:55 ` [PATCH v2 3/6] slab: move validate_slab_ptr() from check_slab() to its callers Vlastimil Babka
2025-09-15 13:55 ` [PATCH v2 4/6] slab: move validate_slab_ptr() from alloc_consistency_checks() to its caller Vlastimil Babka
2025-09-15 13:55 ` [PATCH v2 5/6] slab: validate slab before using it in alloc_single_from_partial() Vlastimil Babka
2025-09-15 14:25   ` Harry Yoo
2025-09-15 14:48     ` Vlastimil Babka
2025-09-15 13:55 ` [PATCH v2 6/6] slab: don't validate slab pointer in free_debug_processing() Vlastimil Babka

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