The implementation of __free_one() was accidentally placed inside a CONFIG_NUMA #ifdef. Move it above. Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Link: https://lore.kernel.org/lkml/7ff248c7-d447-340c-a8e2-8c02972aca70@xxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- This a fix for slab-add-naive-detection-of-double-free.patch --- mm/slab.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index bbff6705ab2b..5ccb151a6e8f 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -588,6 +588,16 @@ static int transfer_objects(struct array_cache *to, return nr; } +/* &alien->lock must be held by alien callers. */ +static __always_inline void __free_one(struct array_cache *ac, void *objp) +{ + /* Avoid trivial double-free. */ + if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && + WARN_ON_ONCE(ac->avail > 0 && ac->entry[ac->avail - 1] == objp)) + return; + ac->entry[ac->avail++] = objp; +} + #ifndef CONFIG_NUMA #define drain_alien_cache(cachep, alien) do { } while (0) @@ -749,16 +759,6 @@ static void drain_alien_cache(struct kmem_cache *cachep, } } -/* &alien->lock must be held by alien callers. */ -static __always_inline void __free_one(struct array_cache *ac, void *objp) -{ - /* Avoid trivial double-free. */ - if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && - WARN_ON_ONCE(ac->avail > 0 && ac->entry[ac->avail - 1] == objp)) - return; - ac->entry[ac->avail++] = objp; -} - static int __cache_free_alien(struct kmem_cache *cachep, void *objp, int node, int page_node) { -- 2.25.1 -- Kees Cook
