From 06283bea26adeb6dfa421419d2aa3979d63e50f1 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Mon, 5 Nov 2007 11:23:51 -0800 Subject: [PATCH] SLUB: Fix memory leak by not reusing cpu_slab backport of 05aa345034de6ae9c77fb93f6a796013641d57d5 from Linus's tree. SLUB: Fix memory leak by not reusing cpu_slab Fix the memory leak that may occur when we attempt to reuse a cpu_slab that was allocated while we reenabled interrupts in order to be able to grow a slab cache. The per cpu freelist may contain objects and in that situation we may overwrite the per cpu freelist pointer loosing objects. This only occurs if we find that the concurrently allocated slab fits our allocation needs. If we simply always deactivate the slab then the freelist will be properly reintegrated and the memory leak will go away. Signed-off-by: Christoph Lameter Cc: Hugh Dickins Signed-off-by: Greg Kroah-Hartman --- mm/slub.c | 22 +--------------------- 1 file changed, 1 insertion(+), 21 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index e0cf6213abc0..648f2c77fee7 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1431,28 +1431,8 @@ new_slab: page = new_slab(s, gfpflags, node); if (page) { cpu = smp_processor_id(); - if (s->cpu_slab[cpu]) { - /* - * Someone else populated the cpu_slab while we - * enabled interrupts, or we have gotten scheduled - * on another cpu. The page may not be on the - * requested node even if __GFP_THISNODE was - * specified. So we need to recheck. - */ - if (node == -1 || - page_to_nid(s->cpu_slab[cpu]) == node) { - /* - * Current cpuslab is acceptable and we - * want the current one since its cache hot - */ - discard_slab(s, page); - page = s->cpu_slab[cpu]; - slab_lock(page); - goto load_freelist; - } - /* New slab does not fit our expectations */ + if (s->cpu_slab[cpu]) flush_slab(s, s->cpu_slab[cpu], cpu); - } slab_lock(page); SetSlabFrozen(page); s->cpu_slab[cpu] = page; -- 2.39.5