INFO: task syz.4.207:5361 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.207 state:D stack:25856 pid:5361 ppid:4278 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
sync_bdevs+0x1ab/0x320 block/bdev.c:1071
ksys_sync+0xb6/0x150 fs/sync.c:105
__ia32_sys_sync+0xa/0x10 fs/sync.c:113
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f74b7b8f749
RSP: 002b:00007f74b8a7f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f74b7de5fa0 RCX: 00007f74b7b8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f74b7de5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f74b7de6038 R14: 00007f74b7de5fa0 R15: 00007ffd3ac9aed8
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8c92bb70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8c92c390 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8c92b1e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8c92b1e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8c92b1e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/u4:3/46:
2 locks held by udevd/3638:
#0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538
#1: ffff8880b8e27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
2 locks held by getty/4032:
#0: ffff88814d3a1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by udevd/4385:
#0: ffff888024eb04c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
2 locks held by kworker/u4:10/4427:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004a3fd00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by udevd/4445:
#0: ffff8880247b54c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by syz.4.207/5361:
#0: ffff8880247b54c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1ab/0x320 block/bdev.c:1071
1 lock held by syz.2.452/6582:
#0: ffff8880247b54c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1ab/0x320 block/bdev.c:1071
1 lock held by syz.3.554/7014:
#0: ffffffff8c930eb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#0: ffffffff8c930eb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962
1 lock held by syz.0.556/7030:
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7014 Comm: syz.3.554 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:hlock_conflict+0x1/0x1f0 kernel/locking/lockdep.c:2004
Code: b9 20 00 00 00 e8 bf aa ff ff 85 c0 78 02 5b c3 89 c7 89 c3 e8 f0 d9 ff ff 89 d8 5b c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 <41> 57 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bc 00 00 00 00 00
RSP: 0018:ffffc900054e6b10 EFLAGS: 00000046
RAX: 1ffff92000a9cd82 RBX: 0000000000000000 RCX: ffffffff969d2103
RDX: ffffffff81643150 RSI: ffff88802e8ce4c0 RDI: ffffc900054e6be0
RBP: 1ffff92000a9cd7e R08: ffffc900054e6bb8 R09: 0000000000000020
R10: fffff52000a9cd82 R11: 1ffff92000a9cd7c R12: dffffc0000000000
R13: ffffc900054e6be0 R14: ffffc900054e6bf0 R15: 1ffffffff205e729
FS: 00007f5795c676c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2fab28 CR3: 000000007578a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__bfs+0x2a3/0x5c0 kernel/locking/lockdep.c:1785
__bfs_forwards kernel/locking/lockdep.c:1830 [inline]
check_path+0x21/0x40 kernel/locking/lockdep.c:2131
check_noncircular+0x16f/0x310 kernel/locking/lockdep.c:2158
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
reacquire_held_locks+0x2f9/0x590 kernel/locking/lockdep.c:5187
__lock_release kernel/locking/lockdep.c:5376 [inline]
lock_release+0x340/0x910 kernel/locking/lockdep.c:5682
up_write+0x29/0x420 kernel/locking/rwsem.c:1625
btrfs_force_cow_block+0xd94/0x18d0 fs/btrfs/ctree.c:533
btrfs_cow_block+0x3c7/0x7e0 fs/btrfs/ctree.c:623
btrfs_search_slot+0xb3f/0x2780 fs/btrfs/ctree.c:-1
btrfs_insert_empty_items+0x99/0x180 fs/btrfs/ctree.c:4185
btrfs_create_new_inode+0xd4a/0x2380 fs/btrfs/inode.c:6560
btrfs_create_common+0x173/0x230 fs/btrfs/inode.c:6791
lookup_open fs/namei.c:3490 [inline]
open_last_lookups fs/namei.c:3558 [inline]
path_openat+0x1187/0x2e70 fs/namei.c:3788
do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
do_sys_openat2+0x142/0x490 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5794d8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5795c67038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5794fe5fa0 RCX: 00007f5794d8f749
RDX: 0000000000000042 RSI: 00002000000000c0 RDI: ffffffffffffff9c
RBP: 00007f5794e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5794fe6038 R14: 00007f5794fe5fa0 R15: 00007ffd7f657ce8