INFO: task kworker/u8:6:1405 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6 state:D stack:20472 pid:1405 tgid:1405 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:1)
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x1472/0x4fe0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7245
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2dc/0x710 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:552
jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x7e4/0x1230 fs/fs-writeback.c:1802
writeback_sb_inodes+0x92e/0x1910 fs/fs-writeback.c:2030
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107
wb_writeback+0x459/0xad0 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0xaf3/0xf00 fs/fs-writeback.c:2403
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Showing all locks held in the system:
6 locks held by kworker/u8:0/12:
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc90000117bc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90000117bc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff888037d4c300 (&devlink->lock_key#13){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:908
#3: ffff88801bbe1120 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#3: ffff88801bbe1120 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:861 [inline]
#3: ffff88801bbe1120 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:921
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#5: ffff8880b8936e50 ((crngs.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#5: ffff8880b8936e50 ((crngs.lock)){+.+.}-{3:3}, at: crng_make_state+0x162/0x5d0 drivers/char/random.c:368
3 locks held by rcuc/1/28:
1 lock held by khungtaskd/38:
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:2/42:
4 locks held by kworker/u8:3/58:
#0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000124fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000124fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffffffff8ef2caa0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0 net/core/net_namespace.c:670
#3: ffff88805b4657b8 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_destruct+0x116/0x310 drivers/net/wireguard/device.c:249
6 locks held by kworker/u8:4/69:
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000154fbc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000154fbc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff88801196c300 (&devlink->lock_key#23){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:908
#3: ffff88805b67c520 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#3: ffff88805b67c520 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:861 [inline]
#3: ffff88805b67c520 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:921
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#5: ffff8880b8936e50 ((crngs.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#5: ffff8880b8936e50 ((crngs.lock)){+.+.}-{3:3}, at: crng_make_state+0x162/0x5d0 drivers/char/random.c:368
4 locks held by kworker/u8:6/1405:
#0: ffff88801e2b0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88801e2b0938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000557fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000557fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff888060e740d0 (&type->s_umount_key#92){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88805a260ba8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
2 locks held by getty/5551:
#0: ffff888026d580a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
7 locks held by kworker/u8:12/7177:
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc90003ca7bc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90003ca7bc0 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff888081e64300 (&devlink->lock_key#60){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:908
#3: ffff888033acfd20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#3: ffff888033acfd20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:861 [inline]
#3: ffff888033acfd20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:921
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#4: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#5: ffff8880b8936e50 ((crngs.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#5: ffff8880b8936e50 ((crngs.lock)){+.+.}-{3:3}, at: crng_make_state+0x162/0x5d0 drivers/char/random.c:368
#6: ffff888027df2908 (&p->pi_lock){-...}-{2:2}, at: task_rq_lock+0x5b/0x460 kernel/sched/core.c:737
4 locks held by syz.1.381/10418:
3 locks held by kworker/u8:5/10494:
#0: ffff88803066f938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88803066f938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc90003aa7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90003aa7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4194
4 locks held by syz-executor/10820:
#0: ffff888033e06480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2683 [inline]
#0: ffff888033e06480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:682
#1: ffff88805cdac078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff888027817968 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027817968 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8e7aa858 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
10 locks held by syz-executor/10823:
4 locks held by syz-executor/10826:
#0: ffff888033e06480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2683 [inline]
#0: ffff888033e06480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:682
#1: ffff88805bf7a078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff888027817968 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027817968 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8e7aa858 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
2 locks held by syz-executor/10865:
#0: ffffffff8f4809d0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8f4809d0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8f4809d0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071
1 lock held by syz-executor/10869:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7177 Comm: kworker/u8:12 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline]
RIP: 0010:__lock_acquire+0x197b/0x2cf0 kernel/locking/lockdep.c:5237
Code: 13 25 ff 0f 00 00 39 05 4f 3b 8e 11 73 06 89 05 47 3b 8e 11 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 10 4a a9
RSP: 0018:ffffc90003ca7018 EFLAGS: 00000006
RAX: ffffffff95c474b8 RBX: 00000000000003cd RCX: 0000000000000438
RDX: ffffffff95b0cb48 RSI: ffff888027df2ae8 RDI: 00000000000003cd
RBP: e0797bf583db6746 R08: ffffc90003ca6fe0 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff819f4dd0 R12: ffffffff95b294e8
R13: ffffffff92ce61d8 R14: ffff888027df1e40 R15: 0000000000000437
FS: 0000000000000000(0000) GS:ffff8881266c9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564e7c9ddb70 CR3: 000000007a358000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline]
do_write_seqcount_begin include/linux/seqlock.h:503 [inline]
psi_write_begin+0xab/0x160 kernel/sched/psi.c:183
psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
psi_sched_switch kernel/sched/stats.h:225 [inline]
__schedule+0x247b/0x4fe0 kernel/sched/core.c:6861
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule_rtlock+0x30/0x70 kernel/sched/core.c:7028
rtlock_slowlock_locked+0x3638/0x3c80 kernel/locking/rtmutex.c:1868
rtlock_slowlock kernel/locking/rtmutex.c:1895 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x165/0x400 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
crng_make_state+0x162/0x5d0 drivers/char/random.c:368
_get_random_bytes+0xff/0x260 drivers/char/random.c:406
eth_random_addr include/linux/etherdevice.h:238 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:825 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
nsim_dev_trap_report_work+0x362/0xbc0 drivers/net/netdevsim/dev.c:921
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246