From: syzbot <syzbot+0f427123ae84b3ba6dc7@syzkaller.appspotmail.com>
To: axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [block?] possible deadlock in bdev_open
Date: Sun, 24 May 2026 16:29:26 -0700 [thread overview]
Message-ID: <6a1389d6.a70a0220.74ee.0000.GAE@google.com> (raw)
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=14e5db06580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0299bf0261ddd5
dashboard link: https://syzkaller.appspot.com/bug?extid=0f427123ae84b3ba6dc7
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+0f427123ae84b3ba6dc7@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.0.336/7301 is trying to acquire lock:
ffff88801b3974c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
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:
-> #6 (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
-> #5 (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
-> #4 (&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
copy_splice_read+0x605/0xab0 fs/splice.c:362
do_splice_read fs/splice.c:980 [inline]
splice_direct_to_actor+0x483/0xc80 fs/splice.c:1084
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
-> #3 (&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
-> #2 ((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
-> #1 ((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
-> #0 (&disk->open_mutex){+.+.}-{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
__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
disk_scan_partitions+0x1c1/0x2c0 block/genhd.c:387
add_disk_final block/genhd.c:416 [inline]
add_disk_fwnode+0x321/0x480 block/genhd.c:610
add_disk include/linux/blkdev.h:794 [inline]
brd_alloc+0x5c9/0x7d0 drivers/block/brd.c:340
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
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
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
other info that might help us debug this:
Chain exists of:
&disk->open_mutex --> system_transition_mutex --> major_names_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(major_names_lock);
lock(system_transition_mutex);
lock(major_names_lock);
lock(&disk->open_mutex);
*** DEADLOCK ***
6 locks held by syz.0.336/7301:
#0: ffff888011240528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1260
#1: ffff888035564480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
#1: ffff888035564480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#2: ffff88801efe3078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#3: ffff88801eec5c38 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#3: ffff88801eec5c38 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#4: ffffffff8de756d8 (system_transition_mutex){+.+.}-{4:4}, at: software_resume+0x47/0x4c0 kernel/power/hibernate.c:1022
#5: ffffffff8e74bdd8 (major_names_lock){+.+.}-{4:4}, at: blk_probe_dev block/genhd.c:881 [inline]
#5: ffffffff8e74bdd8 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x35/0x2a0 block/genhd.c:897
stack backtrace:
CPU: 1 UID: 0 PID: 7301 Comm: syz.0.336 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:
<TASK>
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
__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
disk_scan_partitions+0x1c1/0x2c0 block/genhd.c:387
add_disk_final block/genhd.c:416 [inline]
add_disk_fwnode+0x321/0x480 block/genhd.c:610
add_disk include/linux/blkdev.h:794 [inline]
brd_alloc+0x5c9/0x7d0 drivers/block/brd.c:340
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
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
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
RIP: 0033:0x7f157962ce59
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:00007f157783c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f15798a6180 RCX: 00007f157962ce59
RDX: 0000000000000024 RSI: 0000200000000040 RDI: 000000000000000d
RBP: 00007f15796c2d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f15798a6218 R14: 00007f15798a6180 R15: 00007fffa4f29e08
</TASK>
block device autoloading is deprecated and will be removed.
PM: Image not found (code -22)
---
This report is generated by a bot. It may contain errors.
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reply other threads:[~2026-05-24 23:29 UTC|newest]
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