On Tue, Jun 19, 2018 at 11:34 PM Shakeel Butt shakeelb@google.com wrote:
For !CONFIG_SLUB_DEBUG, SLUB does not maintain the number of slabs allocated per node for a kmem_cache. Thus, slabs_node() in __kmem_cache_empty() will always return 0. So, in such situation, it is required to check per-cpu slabs to make sure if a kmem_cache is empty or not.
Please note that __kmem_cache_shutdown() and __kmem_cache_shrink() are not affected by !CONFIG_SLUB_DEBUG as they call flush_all() to clear per-cpu slabs.
Fixes: f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()") Signed-off-by: Shakeel Butt shakeelb@google.com Reported-by: Jason A . Donenfeld Jason@zx2c4.com Cc: Christoph Lameter cl@linux.com Cc: Pekka Enberg penberg@kernel.org Cc: David Rientjes rientjes@google.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Andrew Morton akpm@linux-foundation.org Cc: stable@vger.kernel.org
mm/slub.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/mm/slub.c b/mm/slub.c index a3b8467c14af..731c02b371ae 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3673,9 +3673,23 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
bool __kmem_cache_empty(struct kmem_cache *s) {
int node;
int cpu, node; struct kmem_cache_node *n;/** slabs_node will always be 0 for !CONFIG_SLUB_DEBUG. So, manually* check slabs for all cpus.*/if (!IS_ENABLED(CONFIG_SLUB_DEBUG)) {for_each_online_cpu(cpu) {struct kmem_cache_cpu *c;c = per_cpu_ptr(s->cpu_slab, cpu);if (c->page || slub_percpu_partial(c))return false;}}for_each_kmem_cache_node(s, node, n) if (n->nr_partial || slabs_node(s, node)) return false;-- 2.18.0.rc1.244.gcf134e6275-goog
I can confirm that this fixes the test case on build.wireguard.com.