From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f207.google.com (mail-oi1-f207.google.com [209.85.167.207]) (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 951C2356779 for ; Sat, 1 Aug 2026 00:24:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785543872; cv=none; b=BAAaKYVF27daT3mFKTbpSmJ45KNRJ2+PU46p4lCHh8A400uJFatL0ooVXcuoVJOW6ZWyj/tefmVzfomX+AvEt0OE45lnMOmLKS/k+Npf7NZj7SOGfdvH5d9KigHoVDwQmQ/lWtOr9ta2DSAIjc+kmW5Hx6KJAyamzlCv8rM3aws= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785543872; c=relaxed/simple; bh=Jm4C9eVzYuv16vfPGCDDQrJ1YLAJqJrglveQILuUms4=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=oaozEe20NG+nyEFYSfgMyyk5uf5Zg5g2PmtWjJrTEDvif+5t+OMYoTvZ/BiI99Gjd2JpH55gF7sOjhSFmAJpw/G/ZZNyMh7seVxZDLadf7+Am4EIcJS+JMJ5Lm1OcDnkhrAnFcR9d9bTz7LFrq9q//BHawTZUHqEpGMS3+ZxHrg= 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=209.85.167.207 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-oi1-f207.google.com with SMTP id 5614622812f47-4a7de733fa9so1793390b6e.3 for ; Fri, 31 Jul 2026 17:24:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785543869; x=1786148669; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=ZXu+HIbdRObJDsHG03Ki649MFVi2v8Dtik0IqjR6sN8=; b=URKbDdAQXt5IlzEvfZjpMg9MvLw2fYTc+jEEPezQyJVX0gbdCWh6K0f320qSp2LR9o eKX72C+qHvFYIAYm4aRepzoFQesBBrwN7SjxoVwbxUSmoE+IGRUkayuVZqQSx5umx3kI 46fY74HQRkJ7bJcDncW5uUNZeqyaGDywAEuPRR+l39rCa3lr36y02bBTdumq/N+Kz0lS VK/0nfGH2g+Zb7UcDQ/NpTBvIX99qdLJlNv5OH4FPXG/4P6V4rtsjAdo+u8fm9yJo9Gq MrOTivdi6M5NbEHYfEEjvtQNjgIUO56KVR2lx3+wyP5WhCKDHDrbQb6f/PXh+y1sYSUK 21Fg== X-Forwarded-Encrypted: i=1; AHgh+RrI0UsUuZOY/D/xZe2LZ4nzeGhiMyPSLJATXizhGlM5FPjqLA4CwUY6MCCBzWgIeBjHJ84hmBj/+gn7U9w=@vger.kernel.org X-Gm-Message-State: AOJu0YzAlh17C3TrfuFdoe4nDoFJNTcLRmLTL7KaPqt5xpfoAxAlYsTC NjumRRrsElN/3h18I8E/+hJAJ4f0Ze+tW2frachIYatjOA/okrb5sWkiYDmXAsGvTO2F7UmxgfD QBxswEQl89Hn6ndOVqRpJTmeU+W4/Ncvk79QjcB1gxGL5YQpKMRKytxD+kgs= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:244f:b0:4a4:9e18:607a with SMTP id 5614622812f47-4af5e3d7eeemr3701046b6e.21.1785543869549; Fri, 31 Jul 2026 17:24:29 -0700 (PDT) Date: Fri, 31 Jul 2026 17:24:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a6d3cbd.6ce73036.24301b.000d.GAE@google.com> Subject: [syzbot] [block?] possible deadlock in blk_probe_dev 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: 62cc90241548 Merge tag 'mm-hotfixes-stable-2026-07-27-14-1.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1715249e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b7079b368dcec295 dashboard link: https://syzkaller.appspot.com/bug?extid=68e1f51046d68329940f compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1d08b858b4e9/disk-62cc9024.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/85154cc68abb/vmlinux-62cc9024.xz kernel image: https://storage.googleapis.com/syzbot-assets/c7121b8e9e61/bzImage-62cc9024.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+68e1f51046d68329940f@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.9.2723/18830 is trying to acquire lock: ffffffff8f793ce0 (major_names_lock){+.+.}-{4:4}, at: blk_probe_dev+0x28/0x1e0 block/genhd.c:877 but task is already holding lock: ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:714 [inline] ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock drivers/md/md.h:1012 [inline] ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock drivers/md/md.h:1004 [inline] ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: md_ioctl+0x112d/0x36b0 drivers/md/md.c:8378 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&mddev->reconfig_mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 mddev_lock_nointr drivers/md/md.h:735 [inline] md_start_sync+0x79/0xbe0 drivers/md/md.c:10190 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 ((work_completion)(&mddev->sync_work)){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 process_one_work+0x98e/0x1940 kernel/workqueue.c:3298 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 ((wq_completion)md_misc){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 touch_wq_lockdep_map+0xad/0x1c0 kernel/workqueue.c:4037 __flush_workqueue+0x131/0x1200 kernel/workqueue.c:4079 md_alloc+0x30/0x10a0 drivers/md/md.c:6313 md_alloc_and_put drivers/md/md.c:6402 [inline] md_probe drivers/md/md.c:6418 [inline] md_probe+0x73/0xf0 drivers/md/md.c:6413 blk_probe_dev+0x149/0x1e0 block/genhd.c:880 blk_request_module+0x16/0xc0 block/genhd.c:893 blkdev_get_no_open+0x9b/0xf0 block/bdev.c:828 blkdev_open+0x141/0x4f0 block/fops.c:663 do_dentry_open+0x6ab/0x14d0 fs/open.c:947 vfs_open+0x82/0x3f0 fs/open.c:1052 do_open fs/namei.c:4700 [inline] path_openat+0x2873/0x4280 fs/namei.c:4863 do_file_open+0x20e/0x430 fs/namei.c:4892 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (major_names_lock){+.+.}-{4:4}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 blk_probe_dev+0x28/0x1e0 block/genhd.c:877 blk_request_module+0x16/0xc0 block/genhd.c:893 blkdev_get_no_open+0x9b/0xf0 block/bdev.c:828 bdev_file_open_by_dev block/bdev.c:1049 [inline] bdev_file_open_by_dev+0x70/0x210 block/bdev.c:1037 md_import_device+0x120/0x360 drivers/md/md.c:3845 md_add_new_disk+0xcc0/0x1820 drivers/md/md.c:7530 md_ioctl+0x2b28/0x36b0 drivers/md/md.c:8476 blkdev_ioctl+0x5ad/0x6f0 block/ioctl.c:797 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 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: major_names_lock --> (work_completion)(&mddev->sync_work) --> &mddev->reconfig_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mddev->reconfig_mutex); lock((work_completion)(&mddev->sync_work)); lock(&mddev->reconfig_mutex); lock(major_names_lock); *** DEADLOCK *** 1 lock held by syz.9.2723/18830: #0: ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:714 [inline] #0: ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock drivers/md/md.h:1012 [inline] #0: ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock drivers/md/md.h:1004 [inline] #0: ffff888050068358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: md_ioctl+0x112d/0x36b0 drivers/md/md.c:8378 stack backtrace: CPU: 0 UID: 0 PID: 18830 Comm: syz.9.2723 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 blk_probe_dev+0x28/0x1e0 block/genhd.c:877 blk_request_module+0x16/0xc0 block/genhd.c:893 blkdev_get_no_open+0x9b/0xf0 block/bdev.c:828 bdev_file_open_by_dev block/bdev.c:1049 [inline] bdev_file_open_by_dev+0x70/0x210 block/bdev.c:1037 md_import_device+0x120/0x360 drivers/md/md.c:3845 md_add_new_disk+0xcc0/0x1820 drivers/md/md.c:7530 md_ioctl+0x2b28/0x36b0 drivers/md/md.c:8476 blkdev_ioctl+0x5ad/0x6f0 block/ioctl.c:797 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1dea79de99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1deb6b0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1deaa26180 RCX: 00007f1dea79de99 RDX: 0000200000001600 RSI: 0000000040140921 RDI: 000000000000000c RBP: 00007f1dea833eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1deaa26218 R14: 00007f1deaa26180 R15: 00007ffcbbaa0f18 md: could not open device unknown-block(0,0). md: md_import_device returned -6 --- This report is generated by a bot. 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