From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7AEEC2D0DB for ; Thu, 26 Dec 2019 21:25:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AA9B820882 for ; Thu, 26 Dec 2019 21:25:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA9B820882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B5C888E0006; Thu, 26 Dec 2019 16:25:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9D38B8E0001; Thu, 26 Dec 2019 16:25:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 910C58E0006; Thu, 26 Dec 2019 16:25:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0151.hostedemail.com [216.40.44.151]) by kanga.kvack.org (Postfix) with ESMTP id 7BA508E0001 for ; Thu, 26 Dec 2019 16:25:11 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 277BF8249980 for ; Thu, 26 Dec 2019 21:25:11 +0000 (UTC) X-FDA: 76308573222.11.wall41_4a51803899631 X-HE-Tag: wall41_4a51803899631 X-Filterd-Recvd-Size: 8244 Received: from mail-il1-f197.google.com (mail-il1-f197.google.com [209.85.166.197]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Thu, 26 Dec 2019 21:25:10 +0000 (UTC) Received: by mail-il1-f197.google.com with SMTP id x69so21587859ill.14 for ; Thu, 26 Dec 2019 13:25:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=RHyjLsdcPao2ajY8JTEr55FeeYChxRbCYPUnLoxRhAA=; b=Gol6e/0JNWEGBydEahVGErAZPCygLiYOzz/idGvt3BEE3L0KWY6AtroCVSxoxA3R8p eqvRjY40/TFLTrBxPrpE0FExK0f3phJgWne0EzC1GZIZoxuUGc85joSSeXao8zWfBFSw EQKtv1rVu218iXJyg3AAU/eHLGyT4y6ebPjjCVD9YWAdcTWi9JNyQiom7mEprw6PwcVy slyN1HG7naHvOsxVa2ObYrlvchbTY88ooiaEIK9B8RXWMRHjicI8f//VaN66wzwnpICp t+CwXawWkFoImsl4VLRYbphmIC2Ta0433gYn5HHwjsH5a3owPsxNMQekoJ1zHH5OUJjw 73vA== X-Gm-Message-State: APjAAAWZ5h5McYkR618yGYr6MVtk99DbzQcRqn1Fu8MfpAgn1cmp67bC 88ri55+5cRVpk7K+/In8UJ8VpJ8J/9ySNPzRSjDjODbMEEmx X-Google-Smtp-Source: APXvYqz0tHDyzk2B+GpzLqcrh/cSckh2ans9lg+8PedO8vY86INkBMiK0oDAW0i5PVIspk6GsP/l2FMGcGrbjCk0IrbRi1uhk6mA MIME-Version: 1.0 X-Received: by 2002:a92:1f16:: with SMTP id i22mr42250801ile.206.1577395510006; Thu, 26 Dec 2019 13:25:10 -0800 (PST) Date: Thu, 26 Dec 2019 13:25:09 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000000b5f9d059aa2037f@google.com> Subject: possible deadlock in shmem_fallocate (4) From: syzbot To: akpm@linux-foundation.org, hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hello, syzbot found the following crash on: HEAD commit: 46cf053e Linux 5.5-rc3 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=162124aee00000 kernel config: https://syzkaller.appspot.com/x/.config?x=ed9d672709340e35 dashboard link: https://syzkaller.appspot.com/bug?extid=7a0d9d0b26efefe61780 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+7a0d9d0b26efefe61780@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 5.5.0-rc3-syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/1852 is trying to acquire lock: ffff888098919cd8 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:791 [inline] ffff888098919cd8 (&sb->s_type->i_mutex_key#13){+.+.}, at: shmem_fallocate+0x15a/0xd40 mm/shmem.c:2735 but task is already holding lock: ffffffff89a41e00 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:4922 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}: __fs_reclaim_acquire mm/page_alloc.c:4084 [inline] fs_reclaim_acquire.part.0+0x24/0x30 mm/page_alloc.c:4095 fs_reclaim_acquire mm/page_alloc.c:4695 [inline] prepare_alloc_pages mm/page_alloc.c:4692 [inline] __alloc_pages_nodemask+0x52d/0x910 mm/page_alloc.c:4744 alloc_pages_vma+0xdd/0x620 mm/mempolicy.c:2170 shmem_alloc_page+0xc0/0x180 mm/shmem.c:1499 shmem_alloc_and_acct_page+0x165/0x990 mm/shmem.c:1524 shmem_getpage_gfp+0x56d/0x29a0 mm/shmem.c:1838 shmem_getpage mm/shmem.c:154 [inline] shmem_write_begin+0x105/0x1e0 mm/shmem.c:2487 generic_perform_write+0x23b/0x540 mm/filemap.c:3309 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3438 generic_file_write_iter+0x420/0x68e mm/filemap.c:3470 call_write_iter include/linux/fs.h:1902 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sb->s_type->i_mutex_key#13){+.+.}: check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 down_write+0x93/0x150 kernel/locking/rwsem.c:1534 inode_lock include/linux/fs.h:791 [inline] shmem_fallocate+0x15a/0xd40 mm/shmem.c:2735 ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline] ashmem_shrink_scan+0x370/0x510 drivers/staging/android/ashmem.c:437 do_shrink_slab+0x40f/0xad0 mm/vmscan.c:526 shrink_slab mm/vmscan.c:687 [inline] shrink_slab+0x19a/0x680 mm/vmscan.c:660 shrink_node_memcgs mm/vmscan.c:2687 [inline] shrink_node+0x46a/0x1ad0 mm/vmscan.c:2791 kswapd_shrink_node mm/vmscan.c:3539 [inline] balance_pgdat+0x7c8/0x11f0 mm/vmscan.c:3697 kswapd+0x5c3/0xf30 mm/vmscan.c:3948 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&sb->s_type->i_mutex_key#13); lock(fs_reclaim); lock(&sb->s_type->i_mutex_key#13); *** DEADLOCK *** 2 locks held by kswapd0/1852: #0: ffffffff89a41e00 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:4922 #1: ffffffff89a1f948 (shrinker_rwsem){++++}, at: shrink_slab mm/vmscan.c:677 [inline] #1: ffffffff89a1f948 (shrinker_rwsem){++++}, at: shrink_slab+0xe6/0x680 mm/vmscan.c:660 stack backtrace: CPU: 0 PID: 1852 Comm: kswapd0 Not tainted 5.5.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1685 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1809 check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 down_write+0x93/0x150 kernel/locking/rwsem.c:1534 inode_lock include/linux/fs.h:791 [inline] shmem_fallocate+0x15a/0xd40 mm/shmem.c:2735 ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline] ashmem_shrink_scan+0x370/0x510 drivers/staging/android/ashmem.c:437 do_shrink_slab+0x40f/0xad0 mm/vmscan.c:526 shrink_slab mm/vmscan.c:687 [inline] shrink_slab+0x19a/0x680 mm/vmscan.c:660 shrink_node_memcgs mm/vmscan.c:2687 [inline] shrink_node+0x46a/0x1ad0 mm/vmscan.c:2791 kswapd_shrink_node mm/vmscan.c:3539 [inline] balance_pgdat+0x7c8/0x11f0 mm/vmscan.c:3697 kswapd+0x5c3/0xf30 mm/vmscan.c:3948 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.