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slab: Warn on duplicate cache names when DEBUG_VM=y

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Duplicate slab cache names can create havoc for userspace tooling that
expects slab cache names to be unique [1]. This is a reasonable
expectation.

Sadly, too many duplicate name problems are out there in the wild, so
simply warn instead of pr_err() + failing the sanity check.

[ vbabka@suse.cz: change to WARN_ON(), see the discussion at [2] ]

Link: https://lore.kernel.org/linux-fsdevel/2d1d053da1cafb3e7940c4f25952da4f0af34e38.1722293276.git.osandov@fb.com/ [1]
Link: https://lore.kernel.org/all/20240807090746.2146479-1-pedro.falcato@gmail.com/ [2]
Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Pedro Falcato 2024-08-07 10:07:46 +01:00 committed by Vlastimil Babka
parent 5be63fc19f
commit 4c39529663
1 changed files with 17 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

17
mm/slab_common.c
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@ -88,6 +88,19 @@ unsigned int kmem_cache_size(struct kmem_cache *s)
EXPORT_SYMBOL(kmem_cache_size);
#ifdef CONFIG_DEBUG_VM
static bool kmem_cache_is_duplicate_name(const char *name)
{
struct kmem_cache *s;
list_for_each_entry(s, &slab_caches, list) {
if (!strcmp(s->name, name))
return true;
}
return false;
}
static int kmem_cache_sanity_check(const char *name, unsigned int size)
{
if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) {
@ -95,6 +108,10 @@ static int kmem_cache_sanity_check(const char *name, unsigned int size)
return -EINVAL;
}
/* Duplicate names will confuse slabtop, et al */
WARN(kmem_cache_is_duplicate_name(name),
"kmem_cache of name '%s' already exists\n", name);
WARN_ON(strchr(name, ' ')); /* It confuses parsers */
return 0;
}