From: Chao Yu <chao@kernel.org>
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>, Hugh Dickins <hugh@veritas.com>
Cc: chao@kernel.org, Chao Yu <chao.yu@oppo.com>,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3] mm/slub: clean up create_unique_id()
Date: Mon, 26 Sep 2022 22:20:41 +0800 [thread overview]
Message-ID: <20220926142042.2725-1-chao@kernel.org> (raw)
From: Chao Yu <chao.yu@oppo.com>
As Christophe JAILLET suggested:
In create_unique_id(),
"looks that ID_STR_LENGTH could even be reduced to 32 or 16.
The 2nd BUG_ON at the end of the function could certainly be just
removed as well or remplaced by a:
if (p > name + ID_STR_LENGTH - 1) {
kfree(name);
return -E<something>;
}
"
According to above suggestion, let's do below cleanups:
1. reduce ID_STR_LENGTH to 32, as the buffer size should be enough;
2. use WARN_ON instead of BUG_ON() and return error if check condition
is true;
3. use snprintf instead of sprintf to avoid overflow.
Link: https://lore.kernel.org/linux-mm/2025305d-16db-abdf-6cd3-1fb93371c2b4@wanadoo.fr/
Fixes: 81819f0fc828 ("SLUB core")
Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Chao Yu <chao.yu@oppo.com>
---
v3:
- clean up codes
- fix size parameter of snprintf()
mm/slub.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 4b98dff9be8e..4d3ee0924533 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5890,7 +5890,7 @@ static inline struct kset *cache_kset(struct kmem_cache *s)
return slab_kset;
}
-#define ID_STR_LENGTH 64
+#define ID_STR_LENGTH 32
/* Create a unique string id for a slab cache:
*
@@ -5924,9 +5924,12 @@ static char *create_unique_id(struct kmem_cache *s)
*p++ = 'A';
if (p != name + 1)
*p++ = '-';
- p += sprintf(p, "%07u", s->size);
+ p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
- BUG_ON(p > name + ID_STR_LENGTH - 1);
+ if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
+ kfree(name);
+ return ERR_PTR(-EINVAL);
+ }
return name;
}
--
2.36.1
next reply other threads:[~2022-09-26 14:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-26 14:20 Chao Yu [this message]
2022-09-26 14:29 ` [PATCH v3] mm/slub: clean up create_unique_id() Vlastimil Babka
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