From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755167AbaA1R1x (ORCPT ); Tue, 28 Jan 2014 12:27:53 -0500 Received: from mga01.intel.com ([192.55.52.88]:34387 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753894AbaA1R1w (ORCPT ); Tue, 28 Jan 2014 12:27:52 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.95,737,1384329600"; d="scan'208";a="472129449" Subject: [PATCH] mm: slub: do not VM_BUG_ON_PAGE() for temporary on-stack pages To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Dave Hansen , sasha.levin@oracle.com, kirill@shutemov.name, akpm@linux-foundation.org, torvalds@linux-foundation.org, penberg@kernel.org From: Dave Hansen Date: Tue, 28 Jan 2014 09:27:49 -0800 Message-Id: <20140128172749.BBF280B1@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen This patch: commit 309381feaee564281c3d9e90fbca8963bb7428ad Author: Sasha Levin Date: Thu Jan 23 15:52:54 2014 -0800 Subject: mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE added a bunch of VM_BUG_ON_PAGE() calls. But, most of the ones in the slub code are for _temporary_ 'struct page's which are declared on the stack and likely have lots of gunk in them. Dumping their contents out will just confuse folks looking at bad_page() output. Plus, if we try to page_to_pfn() on them or soemthing, we'll probably oops anyway. Turn them back in to VM_BUG_ON()s. I believe this is 3.14 material. Signed-off-by: Dave Hansen Cc: Sasha Levin Cc: "Kirill A. Shutemov" Cc: Andrew Morton Cc: Linus Torvalds Cc: Pekka Enberg --- b/mm/slub.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff -puN mm/slub.c~mm-slub-do-not-VM_BUG_ON-stack-pages mm/slub.c --- a/mm/slub.c~mm-slub-do-not-VM_BUG_ON-stack-pages 2014-01-28 09:17:49.869780639 -0800 +++ b/mm/slub.c 2014-01-28 09:19:27.905212000 -0800 @@ -1559,7 +1559,7 @@ static inline void *acquire_slab(struct new.freelist = freelist; } - VM_BUG_ON_PAGE(new.frozen, &new); + VM_BUG_ON(new.frozen); new.frozen = 1; if (!__cmpxchg_double_slab(s, page, @@ -1812,7 +1812,7 @@ static void deactivate_slab(struct kmem_ set_freepointer(s, freelist, prior); new.counters = counters; new.inuse--; - VM_BUG_ON_PAGE(!new.frozen, &new); + VM_BUG_ON(!new.frozen); } while (!__cmpxchg_double_slab(s, page, prior, counters, @@ -1840,7 +1840,7 @@ redo: old.freelist = page->freelist; old.counters = page->counters; - VM_BUG_ON_PAGE(!old.frozen, &old); + VM_BUG_ON(!old.frozen); /* Determine target state of the slab */ new.counters = old.counters; @@ -1952,7 +1952,7 @@ static void unfreeze_partials(struct kme old.freelist = page->freelist; old.counters = page->counters; - VM_BUG_ON_PAGE(!old.frozen, &old); + VM_BUG_ON(!old.frozen); new.counters = old.counters; new.freelist = old.freelist; @@ -2225,7 +2225,7 @@ static inline void *get_freelist(struct counters = page->counters; new.counters = counters; - VM_BUG_ON_PAGE(!new.frozen, &new); + VM_BUG_ON(!new.frozen); new.inuse = page->objects; new.frozen = freelist != NULL; @@ -2319,7 +2319,7 @@ load_freelist: * page is pointing to the page from which the objects are obtained. * That page must be frozen for per cpu allocations to work. */ - VM_BUG_ON_PAGE(!c->page->frozen, c->page); + VM_BUG_ON(!c->page->frozen); c->freelist = get_freepointer(s, freelist); c->tid = next_tid(c->tid); local_irq_restore(flags); _