INFO: task kworker/u8:13:1303 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:13 state:D stack:21504 pid:1303 tgid:1303 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:9)
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7183
__schedule_loop kernel/sched/core.c:7262 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7277
io_schedule+0x80/0xe0 kernel/sched/core.c:8104
TXN_SLEEP_DROP_LOCK fs/jfs/jfs_txnmgr.c:125 [inline]
txBegin+0x27d/0xc00 fs/jfs/jfs_txnmgr.c:375
jfs_commit_inode+0x1b3/0x530 fs/jfs/inode.c:107
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x75d/0x10e0 fs/fs-writeback.c:1825
writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2054
wb_writeback+0x445/0xb00 fs/fs-writeback.c:2239
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3288 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3371
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task syz-executor:10978 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:21240 pid:10978 tgid:10978 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7183
__schedule_loop kernel/sched/core.c:7262 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7277
wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
__writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2845
sync_filesystem+0xa2/0x250 fs/sync.c:54
generic_shutdown_super+0x77/0x2d0 fs/super.c:625
kill_block_super+0x44/0x90 fs/super.c:1725
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b4485da57
RSP: 002b:00007fffb136ff08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5b448f2048 RCX: 00007f5b4485da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffb136ffc0
RBP: 00007fffb136ffc0 R08: 00007fffb1370fc0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffb1371050
R13: 00007f5b448f2048 R14: 00000000000af202 R15: 00007fffb1371090
Showing all locks held in the system:
4 locks held by pr/legacy/17:
4 locks held by rcuc/0/20:
1 lock held by khungtaskd/38:
#0: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
8 locks held by kworker/u8:4/66:
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3371
#1: ffffc9000151fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
#1: ffffc9000151fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3371
#2: ffff88806cbf8310 (&devlink->lock_key#31){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:909
#3: ffff88806007e520 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#3: ffff88806007e520 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:862 [inline]
#3: ffff88806007e520 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:922
#4: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#4: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#5: ffffffff8de5f840 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#6: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#7: ffff8880b8838df8 ((bh_lock)){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#7: ffff8880b8838df8 ((bh_lock)){+...}-{3:3}, at: napi_skb_cache_get+0xbf/0x410 net/core/skbuff.c:289
6 locks held by kworker/0:2/810:
#0: ffff888031f26538 ((wq_completion)mld){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
#0: ffff888031f26538 ((wq_completion)mld){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3371
#1: ffffc90003a47c40 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
#1: ffffc90003a47c40 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3371
#2: ffff88807cf9c628 (&idev->mc_lock){+.+.}-{4:4}, at: mld_ifc_work+0x2d/0xe70 net/ipv6/mcast.c:2692
#3: ffffffff8de5f840 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#4: ffffffff8dfc8400 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#5: ffff8880b8838df8 ((bh_lock)){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#5: ffff8880b8838df8 ((bh_lock)){+...}-{3:3}, at: napi_skb_cache_get+0xbf/0x410 net/core/skbuff.c:289
4 locks held by kworker/u8:9/1116:
2 locks held by kworker/u8:13/1303:
#0: ffff88801b284938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
#0: ffff88801b284938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3371
#1: ffffc9000614fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
#1: ffffc9000614fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3371
2 locks held by kworker/u8:16/1395:
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3263 [inline]
#0: ffff88801a084138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3371
#1: ffffc9000634fc40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3264 [inline]
#1: ffffc9000634fc40 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3371
7 locks held by kworker/u8:19/1533:
3 locks held by dhcpcd/5464:
2 locks held by getty/5554:
#0: ffff88803306c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/10978:
#0: ffff88803cbe60d0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88803cbe60d0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88803cbe60d0 (&type->s_umount_key#77){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
10 locks held by syz-executor/11198:
2 locks held by syz-executor/11625:
3 locks held by kworker/u8:1/12163:
1 lock held by syz-executor/12671:
#0: ffff888062eec0d0 (&type->s_umount_key#61){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888062eec0d0 (&type->s_umount_key#61){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff888062eec0d0 (&type->s_umount_key#61){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
2 locks held by syz.4.945/14598:
2 locks held by syz.8.947/14619:
2 locks held by udevadm/14620:
1 lock held by dhcpcd/14621:
#0: ffff888032b5ccf8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff888032b5ccf8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff888032b5ccf8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
1 lock held by dhcpcd/14622:
#0: ffff88806c42bf78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff88806c42bf78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff88806c42bf78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
1 lock held by dhcpcd/14623:
#0: ffff88806c726138 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff88806c726138 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff88806c726138 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
1 lock held by dhcpcd/14624:
#0: ffff88806c7253b8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff88806c7253b8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff88806c7253b8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
1 lock held by dhcpcd/14625:
#0: ffff88806c723f78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff88806c723f78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff88806c723f78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
1 lock held by dhcpcd/14626:
#0: ffff88806c722478 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff88806c722478 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff88806c722478 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
1 lock held by dhcpcd/14627:
#0: ffff88806c7216f8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
#0: ffff88806c7216f8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:721 [inline]
#0: ffff88806c7216f8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1514
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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+0xfaa/0x1000 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 2e 2d 93 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1f c5 fa fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 da 74 fa 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff336d600 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99b6b690 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff853105c0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b6b400 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126125000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd3284cff8 CR3: 000000007cdd6000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3357
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245