From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 060AC8462 for ; Sun, 24 May 2026 13:36:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779629785; cv=none; b=rgpvlK+wnhzTKFFOE2Ce9HblCk2Vqq0cpY2NHlVgUWGaFegOF/XjJoSMZOpHgqqdLruy0GUymKnoHby4nG4pu/A9GMzddMJ5Glitw3PlWJFIXUmTMO9TOf0ggeHM7mogISvxYpH87Vd7994nbka/NUHP2mmbV1kItQ8BqlXdKh8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779629785; c=relaxed/simple; bh=RUF88D4oxokI6ytz04k5oknLm9XIlC+0WgbXkUL8igU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=tVgT1jUMyqcTYb0KAb0sJ0Xc+sW43meQtiVmDfVzD6JDRQ/dB9gMRf4Q6RO4l6NLJFNkZwQlazUf976fZO4OP2euLtcOSb4Nzv7U8je298SUYYYHtJK1AZ7Evhp1Dv9KxPbmCbR6/iiEPSgZyzAqMnGUU7v2s4VKrlTcGtj9LcY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f78.google.com with SMTP id 006d021491bc7-69d92a86e3bso1677297eaf.1 for ; Sun, 24 May 2026 06:36:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779629782; x=1780234582; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=YZoo+gfHiL9v2AlEyKRRsGzRo7Lz5LerxSDL2g5j4AU=; b=Yme2FYjjVgj3UNS04wVkkZU8UqTi3/6BxijQhhEI9z/7o8WfoMKkkc9RvypeAFR1OI YAAumESXfxuvqIMVAUMiz9H0o9MqMhzA6nKBSVIHM5miaaaD0tYwDOLa/kSXRKCYkDGo georijqcoOWJlEMLakYwb6Ztc9LqjV87kT8u1+YhzrHkOL6HMJDJ4QqxUD87+wv/LQc9 yJd8WB83+O4m9OAKsJx4+QfTaXu6ffor/+xUY04tQUE2wUGWi//+hAmmpiUhBdoj0ljI 2dszzyLFDFVPHap6cqN1Cs0d1pg8EDqM0YlL4xJNsErd9kCQ9yMvhDn5r6Vg2h4HrZu5 9dBg== X-Forwarded-Encrypted: i=1; AFNElJ+HhB9FOJG98/9gOhXHdJDnnwJFNBXRLZdkC9iBKr3gJPsj4ELm3GuLUuXtog1jQGtOeaPvzTdOuDYbiQ==@vger.kernel.org X-Gm-Message-State: AOJu0YzvVkxlVqoNxY9TngSSTuPP9sedW50ihRTEUqVKzCVX2/Y2Gex5 953qhUMb0n951L8zGrki9tg0v0zzXjbfrYtFUaihibmpJdAIPc0MWav9F59fzNT98btwVewhrvQ VHWZ9tNCGv3WQLARM4UgvJtNy6NqcizvBgjIOHnfRGUg48a1vjvsw0xF/ZUQ= Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:8186:b0:696:25d4:1e62 with SMTP id 006d021491bc7-69d7ead4e83mr5563720eaf.2.1779629781709; Sun, 24 May 2026 06:36:21 -0700 (PDT) Date: Sun, 24 May 2026 06:36:21 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a12fed5.050a0220.3c3a9.000b.GAE@google.com> Subject: [syzbot] [block?] possible deadlock in bdev_release (2) From: syzbot To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c1ecb239fa34 Add linux-next specific files for 20260522 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=153a947e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=77a9211ff284de54 dashboard link: https://syzkaller.appspot.com/bug?extid=2f62807dc3239b8f584e compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/4cb88c910144/disk-c1ecb239.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/4a9bc938cf88/vmlinux-c1ecb239.xz kernel image: https://storage.googleapis.com/syzbot-assets/684f1e33f264/bzImage-c1ecb239.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2f62807dc3239b8f584e@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ udevd/5769 is trying to acquire lock: ffff88805ecd4938 ((wq_completion)loop4){+.+.}-{0:0}, at: touch_wq_lockdep_map+0xb5/0x180 kernel/workqueue.c:4033 but task is already holding lock: ffff88802674c4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&disk->open_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 bdev_open+0xe0/0xcc0 block/bdev.c:953 bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1067 swsusp_check+0x56/0x490 kernel/power/swap.c:1571 software_resume+0x51/0x4c0 kernel/power/hibernate.c:1023 resume_store+0x333/0x4f0 kernel/power/hibernate.c:1307 kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x629/0xba0 fs/read_write.c:688 ksys_write+0x156/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (system_transition_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 lock_system_sleep+0x49/0x70 kernel/power/main.c:71 resume_store+0x2ff/0x4f0 kernel/power/hibernate.c:1300 kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x629/0xba0 fs/read_write.c:688 ksys_write+0x156/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 traverse+0x164/0x580 fs/seq_file.c:107 seq_read_iter+0xd09/0xe20 fs/seq_file.c:196 lo_rw_aio+0xc80/0xf00 include/linux/percpu-rwsem.h:-1 do_req_filebacked drivers/block/loop.c:435 [inline] loop_handle_cmd drivers/block/loop.c:1941 [inline] loop_process_work+0x92a/0x11b0 drivers/block/loop.c:1976 process_one_work+0x98b/0x1630 kernel/workqueue.c:3318 process_scheduled_works kernel/workqueue.c:3401 [inline] worker_thread+0xb49/0x1140 kernel/workqueue.c:3482 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 seq_read_iter+0xb8/0xe20 fs/seq_file.c:183 lo_rw_aio+0xc80/0xf00 include/linux/percpu-rwsem.h:-1 do_req_filebacked drivers/block/loop.c:435 [inline] loop_handle_cmd drivers/block/loop.c:1941 [inline] loop_process_work+0x92a/0x11b0 drivers/block/loop.c:1976 process_one_work+0x98b/0x1630 kernel/workqueue.c:3318 process_scheduled_works kernel/workqueue.c:3401 [inline] worker_thread+0xb49/0x1140 kernel/workqueue.c:3482 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 ((work_completion)(&worker->work)){+.+.}-{0:0}: process_one_work+0x8d7/0x1630 kernel/workqueue.c:3294 process_scheduled_works kernel/workqueue.c:3401 [inline] worker_thread+0xb49/0x1140 kernel/workqueue.c:3482 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 ((wq_completion)loop4){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3167 [inline] check_prevs_add kernel/locking/lockdep.c:3286 [inline] validate_chain kernel/locking/lockdep.c:3910 [inline] __lock_acquire+0x15a5/0x2d10 kernel/locking/lockdep.c:5239 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:4033 __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:4075 drain_workqueue+0xd3/0x390 kernel/workqueue.c:4239 __loop_clr_fd drivers/block/loop.c:1130 [inline] lo_release+0x287/0x8f0 drivers/block/loop.c:1767 bdev_release+0x541/0x660 block/bdev.c:-1 blkdev_release+0x15/0x20 block/fops.c:705 __fput+0x461/0xa70 fs/file_table.c:510 fput_close_sync+0x11f/0x240 fs/file_table.c:615 __do_sys_close fs/open.c:1511 [inline] __se_sys_close fs/open.c:1496 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1496 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: (wq_completion)loop4 --> system_transition_mutex --> &disk->open_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&disk->open_mutex); lock(system_transition_mutex); lock(&disk->open_mutex); lock((wq_completion)loop4); *** DEADLOCK *** 1 lock held by udevd/5769: #0: ffff88802674c4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136 stack backtrace: CPU: 0 UID: 0 PID: 5769 Comm: udevd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2045 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3167 [inline] check_prevs_add kernel/locking/lockdep.c:3286 [inline] validate_chain kernel/locking/lockdep.c:3910 [inline] __lock_acquire+0x15a5/0x2d10 kernel/locking/lockdep.c:5239 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:4033 __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:4075 drain_workqueue+0xd3/0x390 kernel/workqueue.c:4239 __loop_clr_fd drivers/block/loop.c:1130 [inline] lo_release+0x287/0x8f0 drivers/block/loop.c:1767 bdev_release+0x541/0x660 block/bdev.c:-1 blkdev_release+0x15/0x20 block/fops.c:705 __fput+0x461/0xa70 fs/file_table.c:510 fput_close_sync+0x11f/0x240 fs/file_table.c:615 __do_sys_close fs/open.c:1511 [inline] __se_sys_close fs/open.c:1496 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1496 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f836530a407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffd5e8529c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007f836521c880 RCX: 00007f836530a407 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008 RBP: 00007f836521c6e8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002 R13: 000055c60f674190 R14: 0000000000000008 R15: 000055c60f683f10 --- This report is generated by a bot. 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