From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (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 5A5393009F2 for ; Sun, 24 May 2026 23:51:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779666692; cv=none; b=aHgPyfp6eBEuu0JpCuq0fo34X0NCCK3kcVQESsn2vjigPtVlG+I0V+zBUklNV/H8T7mJ3bwzitrk6yGU5RLt5I7WW5wJHZfsfAJ8tVRqNiLx5R6vGoZBUzU7GH1XTTC4maeQcuB+eyaMP3/uI4VOqHHYtyr71YGmNv0RrwVe1mc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779666692; c=relaxed/simple; bh=oODVC9qGwahCxOLuKU16MWFSd39wR696YNUcn8mh1l0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=b9amulosjzFcTCa98kto4kilvOJPNxLKc/KDRRzw6uBafiN2KdLlnCCc0aGdX3YwNHo2kV7rKqHhdSbXzB2yQJpPyFMIhfx7qfB01LbujxT0Uj+DfsQfYV09DHDbyxpEq1z/isafe32d3orXo57cdQGCJtlKVoc1or+o082nmTg= 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=209.85.161.80 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-f80.google.com with SMTP id 006d021491bc7-69d77a8f5caso2943025eaf.3 for ; Sun, 24 May 2026 16:51:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779666689; x=1780271489; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=0Z2DJ9klW2KnGrYNzjxmTbrVz0K6vzimOEKz85PWPRA=; b=HvqsvK1Zm4pcaRhKK8Fpd1kwXsTjFDcEI69ippNVFF3VnDUewEpluvNCp1zgT1H0iu hNF6M3u/CuNYLE8fx1SO6ibui+C3MNz4NlbVMlZQSKvQ5i4CnoMtKudyLbhzubRXM6B7 59Fwqs7pEpSyra6baKx7pjscL4okL9JyrDrJTDbBxk7t8DX/4Ceo+OqcDjhMXbNTP48Y wmfof+GJCYarJyeAGuQmnZAG1YbkXBcbxY1AtyS6liQUG8P3Heq6nv+VcVMXEa6+ogwS M92GnMyZy8fv1lPfjRV3zSX5VJiF/GE6H33RngFES6dGiddLlTRHEbxKpLsNNM6yGogx KLIg== X-Forwarded-Encrypted: i=1; AFNElJ+BzgSs/NtU5CYp2CZDItSS3RKJwy/1aanlOvesHnR1IhAg9zHBI6Hp6puojNNF/xi7+4pIos14AcfhMA==@vger.kernel.org X-Gm-Message-State: AOJu0YzipOHK9vlvODz3yIyB+w+20SqSnATqbFaf7mfm6fxlOQGZ0P75 +qfOX+OzpxPellLtEeqrWkfFrPtHNNtp+1OsLce5YYAsTx2PWKh6LqMd0kU8wYV0apCvYNJH6TE h9kfNXfpcKyY5ecXICgrVv/jR3ZTHqiLy2br953GcqCH2TEQqqDyCmHjBdRg= Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:821:b0:69d:b4fb:f319 with SMTP id 006d021491bc7-69db4fbf40emr1036894eaf.7.1779666689306; Sun, 24 May 2026 16:51:29 -0700 (PDT) Date: Sun, 24 May 2026 16:51:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a138f01.050a0220.378d86.0000.GAE@google.com> Subject: [syzbot] [block?] possible deadlock in add_disk_fwnode 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=15526d96580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e0299bf0261ddd5 dashboard link: https://syzkaller.appspot.com/bug?extid=4feabfc9641267769c97 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/b8845b668755/disk-c1ecb239.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/517b638d908a/vmlinux-c1ecb239.xz kernel image: https://storage.googleapis.com/syzbot-assets/dd5e3b587fce/bzImage-c1ecb239.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4feabfc9641267769c97@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.0.2446/19404 is trying to acquire lock: ffff88806b47a410 (&set->update_nr_hwq_lock){++++}-{4:4}, at: add_disk_fwnode+0xe7/0x480 block/genhd.c:596 but task is already holding lock: ffffffff8e74bdd8 (major_names_lock){+.+.}-{4:4}, at: blk_probe_dev block/genhd.c:881 [inline] ffffffff8e74bdd8 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x35/0x2a0 block/genhd.c:897 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (major_names_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 blk_probe_dev block/genhd.c:881 [inline] blk_request_module+0x35/0x2a0 block/genhd.c:897 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:833 bdev_file_open_by_dev+0xa0/0x240 block/bdev.c:1054 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 iter_file_splice_write+0x9a6/0x10f0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x104/0x160 fs/splice.c:1159 splice_direct_to_actor+0x545/0xc80 fs/splice.c:1103 do_splice_direct_actor fs/splice.c:1202 [inline] do_splice_direct+0x19b/0x2a0 fs/splice.c:1228 do_sendfile+0x547/0x7e0 fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1419 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 -> #6 (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 iter_file_splice_write+0x9a6/0x10f0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x104/0x160 fs/splice.c:1159 splice_direct_to_actor+0x545/0xc80 fs/splice.c:1103 do_splice_direct_actor fs/splice.c:1202 [inline] do_splice_direct+0x19b/0x2a0 fs/splice.c:1228 do_sendfile+0x547/0x7e0 fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1419 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 -> #5 (&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 seq_read_iter+0x3f8/0xe20 fs/seq_file.c:226 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x58b/0xa80 fs/read_write.c:574 ksys_read+0x156/0x270 fs/read_write.c:717 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 (&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 -> #3 ((work_completion)(&lo->rootcg_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 -> #2 ((wq_completion)loop1){+.+.}-{0:0}: 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 -> #1 (&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 __del_gendisk+0x127/0x980 block/genhd.c:710 del_gendisk+0xe7/0x160 block/genhd.c:823 loop_remove+0x42/0xc0 drivers/block/loop.c:2136 loop_control_remove drivers/block/loop.c:2195 [inline] loop_control_ioctl+0x4ba/0x5b0 drivers/block/loop.c:2237 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 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 -> #0 (&set->update_nr_hwq_lock){++++}-{4:4}: 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 down_read+0x97/0x200 kernel/locking/rwsem.c:1568 add_disk_fwnode+0xe7/0x480 block/genhd.c:596 add_disk include/linux/blkdev.h:794 [inline] loop_add+0x86e/0xb50 drivers/block/loop.c:2108 blk_probe_dev block/genhd.c:884 [inline] blk_request_module+0x27d/0x2a0 block/genhd.c:-1 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:833 blkdev_open+0x1f5/0x620 block/fops.c:688 do_dentry_open+0x83d/0x13e0 fs/open.c:947 vfs_open+0x3b/0x350 fs/open.c:1052 do_open fs/namei.c:4688 [inline] path_openat+0x2eea/0x3960 fs/namei.c:4847 do_file_open+0x23e/0x4a0 fs/namei.c:4876 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_creat fs/open.c:1452 [inline] __se_sys_creat fs/open.c:1446 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1446 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: &set->update_nr_hwq_lock --> system_transition_mutex --> major_names_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(major_names_lock); lock(system_transition_mutex); lock(major_names_lock); rlock(&set->update_nr_hwq_lock); *** DEADLOCK *** 1 lock held by syz.0.2446/19404: #0: ffffffff8e74bdd8 (major_names_lock){+.+.}-{4:4}, at: blk_probe_dev block/genhd.c:881 [inline] #0: ffffffff8e74bdd8 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x35/0x2a0 block/genhd.c:897 stack backtrace: CPU: 0 UID: 0 PID: 19404 Comm: syz.0.2446 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 down_read+0x97/0x200 kernel/locking/rwsem.c:1568 add_disk_fwnode+0xe7/0x480 block/genhd.c:596 add_disk include/linux/blkdev.h:794 [inline] loop_add+0x86e/0xb50 drivers/block/loop.c:2108 blk_probe_dev block/genhd.c:884 [inline] blk_request_module+0x27d/0x2a0 block/genhd.c:-1 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:833 blkdev_open+0x1f5/0x620 block/fops.c:688 do_dentry_open+0x83d/0x13e0 fs/open.c:947 vfs_open+0x3b/0x350 fs/open.c:1052 do_open fs/namei.c:4688 [inline] path_openat+0x2eea/0x3960 fs/namei.c:4847 do_file_open+0x23e/0x4a0 fs/namei.c:4876 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_creat fs/open.c:1452 [inline] __se_sys_creat fs/open.c:1446 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1446 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: 0033:0x7f1094cfce59 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:00007f1092f56028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f1094f75fa0 RCX: 00007f1094cfce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000000c0 RBP: 00007f1094d92d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1094f76038 R14: 00007f1094f75fa0 R15: 00007fff22949298 block device autoloading is deprecated and will be removed. --- This report 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 issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup