mm, slab: lock the correct nodelist after reenabling irqs

cache_grow() can reenable irqs so the cpu (and node) can change, so ensure
that we take list_lock on the correct nodelist.

This fixes an issue with commit 072bb0aa5e06 ("mm: sl[au]b: add
knowledge of PFMEMALLOC reserve pages") where list_lock for the wrong
node was taken after growing the cache.

Reported-and-tested-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/slab.c b/mm/slab.c
index f8b0d539b4822af7812c8f9edcb51224450f3f64..811af03a14ef168ca8e6ba90ec0af60b2dffa305 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3260,6 +3260,7 @@ force_grow:
 
                /* cache_grow can reenable interrupts, then ac could change. */
                ac = cpu_cache_get(cachep);
+               node = numa_mem_id();
 
                /* no objects in sight? abort */
                if (!x && (ac->avail == 0 || force_refill))