INFO: task syz.0.16:4437 blocked for more than 143 seconds.
Not tainted 5.15.186-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.16 state:D stack:27136 pid: 4437 ppid: 4349 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
schedule+0x11b/0x1e0 kernel/sched/core.c:6459
schedule_timeout+0x97/0x280 kernel/time/timer.c:1890
do_wait_for_common+0x29a/0x440 kernel/sched/completion.c:85
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
flush_workqueue+0x63a/0x1380 kernel/workqueue.c:2882
nbd_start_device_ioctl drivers/block/nbd.c:1365 [inline]
__nbd_ioctl drivers/block/nbd.c:1427 [inline]
nbd_ioctl+0xaea/0xe40 drivers/block/nbd.c:1467
blkdev_ioctl+0x33c/0x690 block/ioctl.c:604
block_ioctl+0xac/0xf0 block/fops.c:496
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7feb53229929
RSP: 002b:00007ffc536e8308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007feb53450fa0 RCX: 00007feb53229929
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007feb532abb39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feb53450fa0 R14: 00007feb53450fa0 R15: 0000000000000002
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/u5:0/146:
#0: ffff888020c4e138 ((wq_completion)nbd2-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000174fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by getty/3951:
#0: ffff88802c5e2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/u5:1/4262:
#0: ffff888020c4d138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc900030afd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:3/4504:
#0: ffff888020cb2138 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000341fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:4/4531:
#0: ffff888020dce138 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc900032ffd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:5/4555:
#0: ffff888020d93938 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000330fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:6/4577:
#0: ffff888020dec938 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000353fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:8/4639:
#0: ffff888020dfb138 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc900037afd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:9/4667:
#0: ffff888020e09938 ((wq_completion)nbd7-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc900038cfd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/u5:10/4695:
#0: ffff888020f28138 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90003bafd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.186-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4434 Comm: kworker/u4:6 Not tainted 5.15.186-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:separate_irq_context kernel/locking/lockdep.c:4541 [inline]
RIP: 0010:__lock_acquire+0xec0/0x7c60 kernel/locking/lockdep.c:4996
Code: 85 db 74 5f 83 fb 31 0f 83 a8 5b 00 00 48 8d 04 9b 48 8b 8c 24 90 00 00 00 48 8d 5c c1 f8 48 89 d8 48 c1 e8 03 42 0f b6 04 00 <84> c0 0f 85 a1 5b 00 00 8b 1b 48 8b 44 24 58 42 0f b6 04 00 84 c0
RSP: 0018:ffffc9000323f820 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff88807baca8f8 RCX: ffff88807baca8b0
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffba0c0
RBP: ffffc9000323fa70 R08: dffffc0000000000 R09: fffffbfff1ff7419
R10: fffffbfff1ff7419 R11: 1ffffffff1ff7418 R12: ffff88807baca920
R13: ffff88807bac9dc0 R14: 1ffff1100f759514 R15: c7b5c6b2436710cd
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555659485c8 CR3: 000000007e215000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287