From: Eric Farman <farman@xxxxxxxxxxxxx> Subject: mm, slub: restore initial kmem_cache flags The routine that applies debug flags to the kmem_cache slabs inadvertantly prevents non-debug flags from being applied to those same objects. That is, if slub_debug=<flag>,<slab> is specified, non-debugged slabs will end up having flags of zero, and the slabs may be unusable. Fix this by including the input flags for non-matching slabs with the contents of slub_debug, so that the caches are created as expected alongside any debugging options that may be requested. With this, we can remove the check for a NULL slub_debug_string, since it's covered by the loop itself. Link: https://lkml.kernel.org/r/20200930161931.28575-1-farman@xxxxxxxxxxxxx Fixes: e17f1dfba37b ("mm, slub: extend slub_debug syntax for multiple blocks") Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) --- a/mm/slub.c~mm-slub-restore-initial-kmem_cache-flags +++ a/mm/slub.c @@ -1413,10 +1413,6 @@ slab_flags_t kmem_cache_flags(unsigned i char *next_block; slab_flags_t block_flags; - /* If slub_debug = 0, it folds into the if conditional. */ - if (!slub_debug_string) - return flags | slub_debug; - len = strlen(name); next_block = slub_debug_string; /* Go through all blocks of debug options, see if any matches our slab's name */ @@ -1450,7 +1446,7 @@ slab_flags_t kmem_cache_flags(unsigned i } } - return slub_debug; + return flags | slub_debug; } #else /* !CONFIG_SLUB_DEBUG */ static inline void setup_object_debug(struct kmem_cache *s, _
