mm: fix race between kmem_cache destroy, create and deactivate

Commit Message

Andrew Morton May 22, 2018, 9:39 p.m. UTC

On Wed, 23 May 2018 05:14:36 +0800 kbuild test robot <[e-mail]> wrote:

> Thank you for the patch! Yet something to improve:
> 
> [auto build test ERROR on mmotm/master]
> [also build test ERROR on v4.17-rc6 next-20180517]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Shakeel-Butt/mm-fix-race-between-kmem_cache-destroy-create-and-deactivate/20180523-041715
> base:   git://git.cmpxchg.org/linux-mmotm.git master
> config: i386-randconfig-x009-201820 (attached as .config)
> compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=i386 
> 
> All errors (new ones prefixed by >>):
> 
>    mm/slub.c: In function '__kmem_cache_alias':
> >> mm/slub.c:4251:4: error: implicit declaration of function 'kmem_cache_put_locked'; did you mean 'kmem_cache_init_late'? [-Werror=implicit-function-declaration]
>        kmem_cache_put_locked(s);
>        ^~~~~~~~~~~~~~~~~~~~~
>        kmem_cache_init_late
>    cc1: some warnings being treated as errors

Thanks.

Patch

--- a/mm/slab.h~mm-fix-race-between-kmem_cache-destroy-create-and-deactivate-v2-fix
+++ a/mm/slab.h
@@ -204,6 +204,8 @@  ssize_t slabinfo_write(struct file *file
 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 
+extern void kmem_cache_put_locked(struct kmem_cache *s);
+
 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 
 /* List of all root caches. */
@@ -296,7 +298,6 @@  extern void slab_init_memcg_params(struc
 extern void memcg_link_cache(struct kmem_cache *s);
 extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
 				void (*deact_fn)(struct kmem_cache *));
-extern void kmem_cache_put_locked(struct kmem_cache *s);
 #else /* CONFIG_MEMCG && !CONFIG_SLOB */
 
 /* If !memcg, all caches are root. */