From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f174.google.com (mail-wi0-f174.google.com [209.85.212.174]) by kanga.kvack.org (Postfix) with ESMTP id 220306B0055 for ; Tue, 11 Mar 2014 14:06:58 -0400 (EDT) Received: by mail-wi0-f174.google.com with SMTP id d1so1304243wiv.7 for ; Tue, 11 Mar 2014 11:06:57 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id n12si21927786wjw.141.2014.03.11.11.06.55 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 11 Mar 2014 11:06:56 -0700 (PDT) Date: Tue, 11 Mar 2014 18:06:52 +0000 From: Mel Gorman Subject: Re: [PATCH -mm] mm,numa,mprotect: always continue after finding a stable thp page Message-ID: <20140311180652.GM10663@suse.de> References: <5318E4BC.50301@oracle.com> <20140306173137.6a23a0b2@cuia.bos.redhat.com> <5318FC3F.4080204@redhat.com> <20140307140650.GA1931@suse.de> <20140307150923.GB1931@suse.de> <20140307182745.GD1931@suse.de> <20140311162845.GA30604@suse.de> <531F3F15.8050206@oracle.com> <531F4128.8020109@redhat.com> <531F48CC.303@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <531F48CC.303@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: Rik van Riel , David Rientjes , Andrew Morton , "linux-mm@kvack.org" , LKML , hhuang@redhat.com, knoel@redhat.com, aarcange@redhat.com On Tue, Mar 11, 2014 at 01:33:00PM -0400, Sasha Levin wrote: > Okay. So just this patch on top of the latest -next shows the following issues: > > 1. BUG in task_numa_work: > > [ 439.417171] BUG: unable to handle kernel paging request at ffff880e17530c00 > [ 439.418216] IP: [] vmacache_find+0x75/0xa0 > [ 439.419073] PGD 8904067 PUD 1028fcb067 PMD 1028f10067 PTE 8000000e17530060 > [ 439.420340] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 439.420340] Dumping ftrace buffer: > [ 439.420340] (ftrace buffer empty) > [ 439.420340] Modules linked in: > [ 439.420340] CPU: 12 PID: 9937 Comm: trinity-c212 Tainted: G W 3.14.0-rc5-next-20140307-sasha-00009-g3b24300-dirty #137 > [ 439.420340] task: ffff880e1a45b000 ti: ffff880e1a490000 task.ti: ffff880e1a490000 > [ 439.420340] RIP: 0010:[] [] vmacache_find+0x75/0xa0 > [ 439.420340] RSP: 0018:ffff880e1a491e68 EFLAGS: 00010286 > [ 439.420340] RAX: ffff880e17530c00 RBX: 0000000000000000 RCX: 0000000000000001 > [ 439.420340] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff880e1a45b000 > [ 439.420340] RBP: ffff880e1a491e68 R08: 0000000000000000 R09: 0000000000000000 > [ 439.420340] R10: 0000000000000001 R11: 0000000000000000 R12: ffff880e1ab75000 > [ 439.420340] R13: ffff880e1ab75000 R14: 0000000000010000 R15: 0000000000000000 > [ 439.420340] FS: 00007f3458c05700(0000) GS:ffff880d2b800000(0000) knlGS:0000000000000000 > [ 439.420340] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 439.420340] CR2: ffff880e17530c00 CR3: 0000000e1a472000 CR4: 00000000000006a0 > [ 439.420340] Stack: > [ 439.420340] ffff880e1a491e98 ffffffff812a7610 ffffffff8118de40 0000000000000117 > [ 439.420340] 00000001000036da ffff880e1a45b000 ffff880e1a491ef8 ffffffff8118de4b > [ 439.420340] ffff880e1a491ec8 ffffffff81269575 ffff880e1ab750a8 ffff880e1a45b000 > [ 439.420340] Call Trace: > [ 439.420340] [] find_vma+0x20/0x90 > [ 439.420340] [] ? task_numa_work+0x130/0x360 > [ 439.420340] [] task_numa_work+0x13b/0x360 > [ 439.420340] [] ? context_tracking_user_exit+0x195/0x1d0 > [ 439.420340] [] task_work_run+0xae/0xf0 > [ 439.420340] [] do_notify_resume+0x8e/0xe0 > [ 439.420340] [] int_signal+0x12/0x17 > [ 439.420340] Code: 42 10 00 00 00 00 48 c7 42 18 00 00 00 00 eb 38 66 0f 1f 44 00 00 31 d2 48 89 c7 48 63 ca 48 8b 84 cf b8 07 00 00 48 85 c0 74 0b <48> 39 30 77 06 48 3b 70 08 72 12 ff c2 83 fa 04 75 de 66 0f 1f > [ 439.420340] RIP [] vmacache_find+0x75/0xa0 > [ 439.420340] RSP > [ 439.420340] CR2: ffff880e17530c00 > Ok, this does not look related. It looks like damage from the VMA caching patches, possibly a use-after free. I'm skeptical that it's related to automatic NUMA balancing as such based on the second trace you posted. What does addr2line -e vmlinux ffffffff81299385 say? I want to be sure it looks like a vma dereference without risking making a mistake decoding it. 1. Does this bug trigger even if automatic NUMA balancing is disabled? 2. Does this bug trigger if DEBUG_PAGEALLOC is disabled? If it's a use-after free then the bug would still be there. 3. Can you test with the following patches reverted please? e15d25d9c827b4346a36a3a78dd566d5ad353402 mm-per-thread-vma-caching-fix-fix e440e20dc76803cdab616b4756c201d5c72857f2 mm-per-thread-vma-caching-fix 0d9ad4220e6d73f63a9eeeaac031b92838f75bb3 mm: per-thread vma caching The last patch will not revert cleanly (least it didn't for me) but it was just a case of git rm the two affected files, remove any include of vmacache.h and commit the rest. Thanks! -- Mel Gorman SUSE Labs -- 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