From 42d623a8cd08eb93ab221d22cee5a62618895bbf Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Wed, 23 Nov 2011 09:14:38 -0600 Subject: [PATCH] slub: use irqsafe_cpu_cmpxchg for put_cpu_partial The cmpxchg must be irq safe. The fallback for this_cpu_cmpxchg only disables preemption which results in per cpu partial page operation potentially failing on non x86 platforms. This patch fixes the following problem reported by Christian Kujau: I seem to hit it with heavy disk & cpu IO is in progress on this PowerBook G4. Full dmesg & .config: http://nerdbynature.de/bits/3.2.0-rc1/oops/ I've enabled some debug options and now it really points to slub.c:2166 http://nerdbynature.de/bits/3.2.0-rc1/oops/oops4m.jpg With debug options enabled I'm currently in the xmon debugger, not sure what to make of it yet, I'll try to get something useful out of it :) Reported-by: Christian Kujau Tested-by: Christian Kujau Acked-by: Eric Dumazet Acked-by: David Rientjes Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- mm/slub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 00efbb56a26..2a9cfd72a3d 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1978,7 +1978,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) page->pobjects = pobjects; page->next = oldpage; - } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); + } while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); stat(s, CPU_PARTIAL_FREE); return pobjects; } -- 2.20.1