INFO: task syz.1.104:4705 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.104 state:D stack:22192 pid: 4705 ppid: 4192 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
wb_wait_for_completion+0x164/0x290 fs/fs-writeback.c:191
sync_inodes_sb+0x1b3/0x920 fs/fs-writeback.c:2781
sync_filesystem+0x16d/0x220 fs/sync.c:64
generic_shutdown_super+0x6b/0x300 fs/super.c:448
kill_block_super+0x7c/0xe0 fs/super.c:1427
deactivate_locked_super+0x93/0xf0 fs/super.c:335
cleanup_mnt+0x418/0x4d0 fs/namespace.c:1148
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x61e/0x20a0 kernel/exit.c:883
do_group_exit+0x12e/0x300 kernel/exit.c:997
get_signal+0x6ca/0x12c0 kernel/signal.c:2900
arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f24e1af2749
RSP: 002b:00007f24dfd38038 EFLAGS: 00000246 ORIG_RAX: 000000000000004b
RAX: ffffffffffffff8b RBX: 00007f24e1d49090 RCX: 00007f24e1af2749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f24e1b76f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f24e1d49128 R14: 00007f24e1d49090 R15: 00007ffebe8cd0f8
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3953:
#0: ffff88802bf6c098 (&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/1:4/4198:
4 locks held by kworker/u4:7/4314:
#0: ffff888018bf4138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc900012efd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffff88807a256650 (sb_internal#3){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x1f1/0xd90 fs/xfs/libxfs/xfs_bmap.c:4573
#3: ffff8880746fa668 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x21e/0xd90 fs/xfs/libxfs/xfs_bmap.c:4578
2 locks held by syz.1.104/4705:
#0: ffff88807a2560e0 (&type->s_umount_key#70){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1:
ffff88802064e7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
ffff88802064e7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x197/0x920 fs/fs-writeback.c:2779
7 locks held by kworker/0:11/4866:
#0:
ffff88814218b138
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1:
ffffc9000391fd00
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2:
ffff888023dae220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
ffff888023dae220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x5560 drivers/usb/core/hub.c:5827
#3: ffff888022cd4220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#3: ffff888022cd4220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:954
#4: ffff888022cd51a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#4: ffff888022cd51a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:954
#5: ffffffff8d1e15e8 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_probe+0x38a/0x1d50 sound/usb/card.c:812
#6:
ffffffff8c24d5b0 (kernfs_rwsem){++++}-{3:3}, at: kernfs_remove_by_name_ns+0x29/0x100 fs/kernfs/dir.c:1561
4 locks held by kworker/u4:16/5811:
#0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90003aa7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffffffff8d22cd10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589
#3:
ffffffff8d238988
(
rtnl_mutex
){+.+.}-{3:3}
, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
4 locks held by udevd/7138:
#0:
ffff888022c65c30
(
&p->lock
){+.+.}-{3:3}
, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
#1:
ffff88801d5ef888
(
&of->mutex
){+.+.}-{3:3}, at: psi_task_switch+0x4d6/0x810 kernel/sched/psi.c:891
#2: ffff88807d0e2d58 (&ep->lock){....}-{2:2}, at: ep_poll_callback+0x7b/0x9f0 fs/eventpoll.c:1176
#3:
ffff88807d0e2ca8
(
&ep->wq
){....}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:137 [inline]
){....}-{2:2}, at: __wake_up_sync_key kernel/sched/wait.c:205 [inline]
){....}-{2:2}, at: __wake_up_sync+0xeb/0x180 kernel/sched/wait.c:237
3 locks held by syz.5.860/7293:
#0: ffffffff8d22cd10 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x32e/0x5b0 net/core/net_namespace.c:499
#1: ffffffff8d238988 (rtnl_mutex){+.+.}-{3:3}, at: vti6_exit_batch_net+0xb3/0x410 net/ipv6/ip6_vti.c:1185
#2: ffffffff8c1211e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#2: ffffffff8c1211e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
3 locks held by syz.2.867/7320:
#0:
ffffffff8d295710
(
cb_lock
){++++}-{3:3}
, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
#1:
ffffffff8d295568
(
genl_mutex
){+.+.}-{3:3}
, at: genl_lock net/netlink/genetlink.c:33 [inline]
, at: genl_rcv_msg+0x137/0xf40 net/netlink/genetlink.c:790
#2:
ffffffff8d238988
(
rtnl_mutex
){+.+.}-{3:3}
, at: __tipc_nl_compat_doit net/tipc/netlink_compat.c:362 [inline]
, at: tipc_nl_compat_doit+0x20c/0x5f0 net/tipc/netlink_compat.c:397
1 lock held by syz.2.867/7322:
#0:
ffffffff8d238988
(
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681
1 lock held by syz.2.867/7324:
#0:
ffffffff8d238988
(
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
, at: rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2367 Comm: kworker/1:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: xfs-buf/loop1 xfs_buf_ioend_work
RIP: 0010:io_serial_out+0x78/0xb0 drivers/tty/serial/8250/8250_port.c:468
Code: 3f 32 fd 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 b0 a7 76 fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 44 89 f9 80 e1 07 38 c1 7c aa 4c 89 ff
RSP: 0018:ffffc900067af348 EFLAGS: 00000002
RAX: 0000000000000020 RBX: 0000000000000020 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52000cf5e54 R11: 1ffff92000cf5e54 R12: dffffc0000000000
R13: 1ffffffff2c20f30 R14: ffffffff963eb840 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbd0a73d7b0 CR3: 000000002af52000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
uart_console_write+0xaa/0x100 drivers/tty/serial/serial_core.c:1981
serial8250_console_write+0xbb5/0xf80 drivers/tty/serial/8250/8250_port.c:3386
call_console_drivers kernel/printk/printk.c:-1 [inline]
console_unlock+0xc86/0x1200 kernel/printk/printk.c:2744
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xcc/0x110 kernel/printk/printk.c:2299
print_hex_dump+0x1a5/0x260 lib/hexdump.c:285
xfs_hex_dump+0x39/0x50 fs/xfs/xfs_message.c:118
xfs_buf_verifier_error+0x1ba/0x290 fs/xfs/xfs_error.c:418
xfs_agfl_read_verify+0x1bf/0x240 fs/xfs/libxfs/xfs_alloc.c:-1
xfs_buf_ioend+0x25c/0x6e0 fs/xfs/xfs_buf.c:1263
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