INFO: task kworker/1:4:5723 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4 state:D stack:23024 pid:5723 tgid:5723 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: events drain_vmap_area_work
Call Trace:
context_switch kernel/sched/core.c:5520 [inline]
__schedule+0x1259/0x6920 kernel/sched/core.c:7270
__schedule_loop kernel/sched/core.c:7347 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7362
schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
__flush_
__flush_work+0x7c7/0xcb0 kernel/workqueue.c:4439
__purge_vmap_area_lazy+0x879/0xc00 mm/vmalloc.c:2427
drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2452
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
process_scheduled_works kernel/workqueue.c:3470 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
locks held by kworker/0:1/10: 2, last CPU#0:
#0: ffff88801c057140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc900000f7d08 ((work_completion)(&vn->purge_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
locks held by kworker/u8:1/13: 2, last CPU#0:
#0: ffff88807fa08140 ((wq_completion)wg-kex-wg2#7){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc90000127d08 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
locks held by pr/ttyS0/16: 2, last CPU#0:
#0: ffffffff8edd8338 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
#0: ffffffff8edd8338 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline]
#0: ffffffff8edd8338 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x49/0x60 kernel/printk/printk.c:291
#1: ffffffff8edebf40 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8edebf40 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2644 [inline]
#1: ffffffff8edebf40 (rcu_callback){....}-{0:0}, at: rcu_core+0x58f/0x1260 kernel/rcu/tree.c:2919
locks held by khungtaskd/32: 1, last CPU#1:
#0: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6837
locks held by kworker/u8:4/60: 8, last CPU#1:
#0: ffff88801d2d8940 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc9000202fd08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffffffff90cb6388 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:677
#3: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#3: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:249
#4: ffff88801d2bf2a0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x49/0x120 fs/kernfs/dir.c:1791
#5: ffff88801d2bf180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x51/0x120 fs/kernfs/dir.c:1792
#6: ffff88801d2bf210 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: __kernfs_remove+0x3fe/0xb80 fs/kernfs/dir.c:1589
#7: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#7: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#7: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: find_inode_fast+0xa5/0xa30 fs/inode.c:1081
locks held by kworker/u8:5/164: 3, on CPU#0:
#0: ffff88801c094140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc9000203fd08 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:313
locks held by kworker/0:2/1218: 3, on CPU#0:
#0: ffff88801c057140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc9000567fd08 (netdev_work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: netdev_work_proc+0x71/0x880 net/core/netdev_work.c:132
locks held by kworker/u8:11/4415: 3, last CPU#1:
#0: ffff88801c094140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc9001023fd08 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffff888031481258 (&devlink->lock_key#6){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x56/0xd20 drivers/net/netdevsim/dev.c:834
locks held by syslogd/4960: 1, last CPU#1:
#0: ffff88807ed58e70 (&u->iolock){+.+.}-{4:4}, at: __unix_dgram_recvmsg+0x255/0xc30 net/unix/af_unix.c:2587
locks held by dhcpcd/5273: 1, on CPU#1:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x1bd/0x1f10 net/ipv4/devinet.c:1120
locks held by getty/5364: 2, on CPU#0:
#0: ffff8880378d50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000321e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by kworker/0:4/5709: 3, on CPU#0:
#0: ffff88801c057140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc90002567d08 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
locks held by kworker/1:4/5723: 3, on CPU#1:
#0: ffff88801c057140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
#1: ffffc9000408fd08 (drain_vmap_work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
#2: ffffffff8efc1640 (vmap_purge_lock){+.+.}-{4:4}, at: drain_vmap_area_work+0x17/0x40 mm/vmalloc.c:2451
locks held by syz-executor/12141: 1, on CPU#0:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
locks held by syz-executor/12154: 1, on CPU#1:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
locks held by syz-executor/12160: 1, on CPU#0:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xac3/0x2620 net/core/rtnetlink.c:4214
locks held by syz-executor/12168: 1, on CPU#1:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xac3/0x2620 net/core/rtnetlink.c:4214
locks held by syz-executor/12192: 1, on CPU#0:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
locks held by syz-executor/12214: 1, on CPU#1:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
locks held by syz-executor/12223: 1, on CPU#1:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
locks held by syz-executor/12232: 1, on CPU#0:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
locks held by syz-executor/12236: 1, on CPU#1:
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90ccee80 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x31c/0x18c0 net/ipv4/devinet.c:978
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
RIP: 0010:preempt_count_add+0x1e/0x150 kernel/sched/core.c:5997
Code: 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 ba 00 00 00 00 00 fc ff df 48 63 c7 55 53 48 89 c3 65 48 01 05 4a dd b4 12 <48> c7 c0 c0 35 99 9b 48 89 c1 83 e0 07 48 c1 e9 03 83 c0 03 0f b6
RSP: 0018:ffffc90000157938 EFLAGS: 00000082
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8c620c00 RDI: 0000000000000001
RBP: 0000027885a4bd38 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000000007ce R11: 205d323354202020 R12: 0000000000000000
R13: 0000000000000af1 R14: fffffbfff378c1e9 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888123b64000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055de04d8dbe0 CR3: 000000000eb96000 CR4: 00000000003526f0
Call Trace:
delay_tsc+0x3c/0xc0 arch/x86/lib/delay.c:77
udelay include/asm-generic/delay.h:62 [inline]
wait_for_lsr+0xf3/0x210 drivers/tty/serial/8250/8250_port.c:2019
serial8250_fifo_wait_for_lsr_thre+0x5f/0xd0 drivers/tty/serial/8250/8250_port.c:3270
__serial8250_console_fifo_write+0xa5/0x290 drivers/tty/serial/8250/8250_port.c:3345
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
serial8250_console_write+0xf46/0x1330 drivers/tty/serial/8250/8250_port.c:3493
nbcon_emit_next_record+0x8f7/0xa70 kernel/printk/nbcon.c:1070
nbcon_emit_one+0x1a8/0x2b0 kernel/printk/nbcon.c:1157
nbcon_kthread_func+0x613/0x7d0 kernel/printk/nbcon.c:1271
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245