INFO: task syz-executor:4192 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D
stack:21968 pid: 4192 ppid: 1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
wb_wait_for_completion+0x171/0x290 fs/fs-writeback.c:191
sync_inodes_sb+0x1bd/0x950 fs/fs-writeback.c:2787
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+0x42d/0x4e0 fs/namespace.c:1148
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
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: 0033:0x7f356d37c897
RSP: 002b:00007ffe1c8e4998 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f356d410ef0 RCX: 00007f356d37c897
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe1c8e4a50
RBP: 00007ffe1c8e4a50 R08: 00007ffe1c8e5a50 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe1c8e5ae0
R13: 00007f356d410ef0 R14: 0000000000010874 R15: 00007ffe1c8e5b20
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0:
ffffffff8c31eaa0
(rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
1 lock held by dhcpcd/3854:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681
2 locks held by getty/3949:
#0: ffff88802bc90098 (&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+0x5df/0x1a70 drivers/tty/n_tty.c:2158
2 locks held by syz-executor/4184:
#0:
ffff8880792360e0
(
&type->s_umount_key
#56
){+.+.}-{3:3}
, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1:
ffff8880200ce7d8
(
&bdi->wb_switch_rwsem
){+.+.}-{3:3}
, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
2 locks held by syz-executor/4185:
#0: ffff8880242960e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1: ffff8880200ba7d8
(&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
(&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
2 locks held by syz-executor/4192:
#0: ffff88801ee4c0e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1:
ffff8880200547d8
(&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
(&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
3 locks held by kworker/0:4/4225:
#0:
ffff88802b240d38
((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1:
ffffc9000316fd00
((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
3 locks held by kworker/0:5/4226:
#0:
ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1:
ffffc9000317fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
7 locks held by kworker/u4:5/4236:
3 locks held by kworker/u4:9/4352:
#0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1:
ffffc900033efd00
(
(linkwatch_work).work
){+.+.}-{0:0}
, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2:
ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
5 locks held by kworker/u4:10/4354:
#0: ffff888016dcd938
(
(wq_completion)netns
){+.+.}-{0:0}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000348fd00 (net_cleanup_work){+.+.}-{0:0}
, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffffffff8d430950 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
#3: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock_unregistering net/core/dev.c:11633 [inline]
#3: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0x165/0x3c0 net/core/dev.c:11671
#4: ffffffff8c323430 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043
6 locks held by kworker/u4:13/4361:
3 locks held by kworker/1:21/5343:
#0: ffff88802b240d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000305fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
2 locks held by kworker/0:12/5789:
#0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900041afd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
1 lock held by syz-executor/6456:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681
1 lock held by syz.5.740/6903:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: dev_ifconf+0x1a6/0x300 net/core/dev_ioctl.c:64
1 lock held by syz.5.740/6905:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x258/0x1a70 net/ipv4/devinet.c:1076
1 lock held by syz.6.745/6916:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: wext_ioctl_dispatch+0xaf/0x470 net/wireless/wext-core.c:996
1 lock held by syz.9.747/6940:
#0: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#0: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
=============================================
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 02/12/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 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: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:format_decode+0x6c7/0x1300 lib/vsprintf.c:2608
Code: fd 45 31 f6 eb 53 e8 48 14 72 fd eb 13 e8 41 14 72 fd eb 0c e8 3a 14 72 fd eb 05 e8 33 14 72 fd 4d 8d 7c 24 01 4c 89 7c 24 38 <4c> 89 f8 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 26 06 00 00 41 0f b6
RSP: 0018:ffffc9000172e0b0 EFLAGS: 00000293
RAX: ffffffff84070df8 RBX: dffffc0000000000 RCX: ffff8880199c8000
RDX: 0000000000000000 RSI: ffffffff8c93e0c0 RDI: 000000000000006c
RBP: 000000000000006c R08: ffff8880199c8000 R09: 0000000000000005
R10: 000000000000007a R11: 0000000000000000 R12: ffffffff8a2bde03
R13: 000000000000006c R14: 000000000000006c R15: ffffffff8a2bde04
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff2176895c CR3: 000000007506c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vsnprintf+0xef/0x1c20 lib/vsprintf.c:2763
sprintf+0xe4/0x140 lib/vsprintf.c:3013
print_time kernel/printk/printk.c:1274 [inline]
info_print_prefix+0x168/0x360 kernel/printk/printk.c:1300
record_print_text kernel/printk/printk.c:1349 [inline]
console_unlock+0x66e/0x1120 kernel/printk/printk.c:2725
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xda/0x130 kernel/printk/printk.c:2299
_udf_err+0x135/0x190 fs/udf/super.c:2365
udf_bitmap_new_block fs/udf/balloc.c:357 [inline]
udf_new_block+0x15b9/0x1a90 fs/udf/balloc.c:730
inode_getblk fs/udf/inode.c:768 [inline]
udf_get_block+0x11b4/0x4140 fs/udf/inode.c:358
__mpage_writepage+0x4bc/0x1ac0 fs/mpage.c:564
write_cache_pages+0x9b7/0x1000 mm/page-writeback.c:2277
mpage_writepages+0x113/0x290 fs/mpage.c:712
do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
__writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
wb_writeback+0x45d/0xbe0 fs/fs-writeback.c:2114
wb_do_writeback fs/fs-writeback.c:2257 [inline]
wb_workfn+0x43a/0xf20 fs/fs-writeback.c:2298
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287