From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f179.google.com (mail-pd0-f179.google.com [209.85.192.179]) by kanga.kvack.org (Postfix) with ESMTP id 36E186B0031 for ; Thu, 19 Dec 2013 00:55:11 -0500 (EST) Received: by mail-pd0-f179.google.com with SMTP id r10so666025pdi.24 for ; Wed, 18 Dec 2013 21:55:10 -0800 (PST) Received: from LGEMRELSE6Q.lge.com (LGEMRELSE6Q.lge.com. [156.147.1.121]) by mx.google.com with ESMTP id zi8si1737478pac.127.2013.12.18.21.55.08 for ; Wed, 18 Dec 2013 21:55:09 -0800 (PST) Date: Thu, 19 Dec 2013 14:55:10 +0900 From: Joonsoo Kim Subject: Re: [PATCH v3] mm/rmap: fix BUG at rmap_walk Message-ID: <20131219055510.GA27532@lge.com> References: <1387431715-6786-1-git-send-email-liwanp@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1387431715-6786-1-git-send-email-liwanp@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Wanpeng Li Cc: Andrew Morton , Sasha Levin , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Dec 19, 2013 at 01:41:55PM +0800, Wanpeng Li wrote: > This bug is introduced by commit 37f093cdf(mm/rmap: use rmap_walk() in > page_referenced()). page_get_anon_vma() called in page_referenced_anon() > will lock and increase the refcount of anon_vma. PageLocked is not required > by page_referenced_anon() and there is not any assertion before, commit > 37f093cdf introduced this extra BUG_ON() checking for anon page by mistake. > This patch fix it by remove rmap_walk()'s VM_BUG_ON() and comment reason why > the page must be locked for rmap_walk_ksm() and rmap_walk_file(). > > [ 588.698828] kernel BUG at mm/rmap.c:1663! > [ 588.699380] invalid opcode: 0000 [#2] PREEMPT SMP DEBUG_PAGEALLOC > [ 588.700347] Dumping ftrace buffer: > [ 588.701186] (ftrace buffer empty) > [ 588.702062] Modules linked in: > [ 588.702759] CPU: 0 PID: 4647 Comm: kswapd0 Tainted: G D W 3.13.0-rc4-next-20131218-sasha-00012-g1962367-dirty #4155 > [ 588.704330] task: ffff880062bcb000 ti: ffff880062450000 task.ti: ffff880062450000 > [ 588.705507] RIP: 0010:[] [] rmap_walk+0x10/0x50 > [ 588.706800] RSP: 0018:ffff8800624518d8 EFLAGS: 00010246 > [ 588.707515] RAX: 000fffff80080048 RBX: ffffea00000227c0 RCX: 0000000000000000 > [ 588.707515] RDX: 0000000000000000 RSI: ffff8800624518e8 RDI: ffffea00000227c0 > [ 588.707515] RBP: ffff8800624518d8 R08: ffff8800624518e8 R09: 0000000000000000 > [ 588.707515] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800624519d8 > [ 588.707515] R13: 0000000000000000 R14: ffffea00000227e0 R15: 0000000000000000 > [ 588.707515] FS: 0000000000000000(0000) GS:ffff880065200000(0000) knlGS:0000000000000000 > [ 588.707515] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 588.707515] CR2: 00007fec40cbe0f8 CR3: 00000000c2382000 CR4: 00000000000006f0 > [ 588.707515] Stack: > [ 588.707515] ffff880062451958 ffffffff81289f4b ffff880062451918 ffffffff81289f80 > [ 588.707515] 0000000000000000 0000000000000000 ffffffff8128af60 0000000000000000 > [ 588.707515] 0000000000000024 0000000000000000 0000000000000000 0000000000000286 > [ 588.707515] Call Trace: > [ 588.707515] [] page_referenced+0xcb/0x100 > [ 588.707515] [] ? page_referenced+0x100/0x100 > [ 588.707515] [] ? invalid_page_referenced_vma+0x170/0x170 > [ 588.707515] [] shrink_active_list+0x212/0x330 > [ 588.707515] [] ? inactive_file_is_low+0x33/0x50 > [ 588.707515] [] shrink_lruvec+0x2d5/0x300 > [ 588.707515] [] shrink_zone+0x96/0x1e0 > [ 588.707515] [] kswapd_shrink_zone+0xf6/0x1c0 > [ 588.707515] [] balance_pgdat+0x373/0x550 > [ 588.707515] [] kswapd+0x2f3/0x350 > [ 588.707515] [] ? perf_trace_mm_vmscan_lru_isolate_template+0x120/0x120 > [ 588.707515] [] kthread+0x105/0x110 > [ 588.707515] [] ? set_kthreadd_affinity+0x30/0x30 > [ 588.707515] [] ret_from_fork+0x7c/0xb0 > [ 588.707515] [] ? set_kthreadd_affinity+0x30/0x30 > [ 588.707515] Code: c0 48 83 c4 18 89 d0 5b 41 5c 41 5d 41 5e 41 5f c9 c3 66 0f 1f 84 > 00 00 00 00 00 55 48 89 e5 66 66 66 66 90 48 8b 07 a8 01 75 10 <0f> 0b 66 0f 1f 44 00 0 > 0 eb fe 66 0f 1f 44 00 00 f6 47 08 01 74 > [ 588.707515] RIP [] rmap_walk+0x10/0x50 > [ 588.707515] RSP > > Reported-by: Sasha Levin > Signed-off-by: Wanpeng Li Reviewed-by: Joonsoo Kim Thanks for all relevant people. :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org