diff options
| author | Vlastimil Babka <vbabka@suse.cz> | 2022-11-16 15:56:32 +0100 |
|---|---|---|
| committer | Vlastimil Babka <vbabka@suse.cz> | 2022-11-27 23:35:04 +0100 |
| commit | 346907ceb9d11b9e22677c142b45ff50dd20a66a (patch) | |
| tree | a322488eba1e68b6ade9ea8e6e09a1deb784b99b /mm/slub.c | |
| parent | c18c20f16219516b12a4f2fd29c25e06be97e064 (diff) | |
mm, slab: ignore hardened usercopy parameters when disabled
With CONFIG_HARDENED_USERCOPY not enabled, there are no
__check_heap_object() checks happening that would use the struct
kmem_cache useroffset and usersize fields. Yet the fields are still
initialized, preventing merging of otherwise compatible caches.
Also the fields contribute to struct kmem_cache size unnecessarily when
unused. Thus #ifdef them out completely when CONFIG_HARDENED_USERCOPY is
disabled. In kmem_dump_obj() print object_size instead of usersize, as
that's actually the intention.
In a quick virtme boot test, this has reduced the number of caches in
/proc/slabinfo from 131 to 111.
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c index 157527d7101b..e32db8540767 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5502,11 +5502,13 @@ static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) SLAB_ATTR_RO(cache_dma); #endif +#ifdef CONFIG_HARDENED_USERCOPY static ssize_t usersize_show(struct kmem_cache *s, char *buf) { return sysfs_emit(buf, "%u\n", s->usersize); } SLAB_ATTR_RO(usersize); +#endif static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) { @@ -5803,7 +5805,9 @@ static struct attribute *slab_attrs[] = { #ifdef CONFIG_FAILSLAB &failslab_attr.attr, #endif +#ifdef CONFIG_HARDENED_USERCOPY &usersize_attr.attr, +#endif #ifdef CONFIG_KFENCE &skip_kfence_attr.attr, #endif |