INFO: task syz.4.3956:25231 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.3956 state:D stack:24648 pid:25231 tgid:25230 ppid:18718 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
__schedule_loop kernel/sched/core.c:6944 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6959
io_schedule+0x80/0xd0 kernel/sched/core.c:7791
folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1148 [inline]
migrate_folio_unmap mm/migrate.c:1242 [inline]
migrate_pages_batch+0x14cd/0x35e0 mm/migrate.c:1883
migrate_pages_sync mm/migrate.c:2027 [inline]
migrate_pages+0x2038/0x2930 mm/migrate.c:2109
compact_zone+0x2489/0x4730 mm/compaction.c:2638
compact_node mm/compaction.c:2907 [inline]
compact_nodes mm/compaction.c:2929 [inline]
sysctl_compaction_handler+0x3a4/0x7b0 mm/compaction.c:2980
proc_sys_call_handler+0x4cb/0x700 fs/proc/proc_sysctl.c:600
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f639918efc9
RSP: 002b:00007f639a107038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f63993e5fa0 RCX: 00007f639918efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000b
RBP: 00007f6399211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f63993e6038 R14: 00007f63993e5fa0 R15: 00007ffc860b0798
Showing all locks held in the system:
6 locks held by kworker/0:0/9:
#0: ffff88814228bd48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x841/0x15d0 kernel/workqueue.c:3242
#1: ffffc900000e7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x868/0x15d0 kernel/workqueue.c:3243
#2: ffff88802953b198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff88802953b198 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0 drivers/usb/core/hub.c:5899
#3: ffff8880b863a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
#4: ffffffff99c7c448 (&____s->seqcount#2){----}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#4: ffffffff99c7c448 (&____s->seqcount#2){----}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#4: ffffffff99c7c448 (&____s->seqcount#2){----}-{0:0}, at: tipc_bearer_xmit_skb+0xa9/0x400 net/tipc/bearer.c:568
#5: ffff8880b8627ad8 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1781 [inline]
#5: ffff8880b8627ad8 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1841
1 lock held by khungtaskd/31:
#0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5591:
#0: ffff88814d23d0a0 (
&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
5 locks held by kworker/0:5/5929:
#0: ffff88814228bd48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x841/0x15d0 kernel/workqueue.c:3242
#1: ffffc9000445fba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x868/0x15d0 kernel/workqueue.c:3243
#2: ffff8880290f7198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff8880290f7198 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0 drivers/usb/core/hub.c:5899
#3: ffff888031a70198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff888031a70198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1006
#4: ffff888078426160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff888078426160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1006
1 lock held by udevd/23530:
#0: ffff88802654b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
2 locks held by syz.4.3956/25231:
#0: ffff888077625278 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1232
#1: ffff888057980420 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3195 [inline]
#1: ffff888057980420 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682
4 locks held by udevd/26382:
#0: ffff888062520b08 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:182
#1: ffff88806bde8488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2: ffff8880741f42d8 (kn->active#22){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8880741f42d8 (kn->active#22){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff888031a70198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:919 [inline]
#3: ffff888031a70198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
3 locks held by kworker/1:7/27105:
#0: ffff88801b055948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x841/0x15d0 kernel/workqueue.c:3242
#1: ffffc9000cf1fba0 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x868/0x15d0 kernel/workqueue.c:3243
#2: ffffffff8e3432c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:337 [inline]
watchdog+0xfa9/0xff0 kernel/hung_task.c:500
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 26442 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_in+0x7b/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ff 89 05 fd 41 03 1e 89 da ec 0f b6 c0 5b <41> 5c 41 5e 41 5f e9 1a a0 3f 06 cc 44 89 f9 80 e1 07 38 c1 7c a5
RSP: 0018:ffffc9000a80f360 EFLAGS: 00000006
RAX: 0000000000000005 RBX: ffffffff99f8c190 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc9000a80f530 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85214840 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff99f8c180 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125a9c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c368832 CR3: 000000003468e000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000081
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
serial_port_in include/linux/serial_core.h:806 [inline]
serial8250_console_write+0x584/0x1ba0 drivers/tty/serial/8250/8250_port.c:3306
console_emit_next_record kernel/printk/printk.c:3108 [inline]
console_flush_one_record kernel/printk/printk.c:3194 [inline]
console_flush_all+0x6f6/0xb10 kernel/printk/printk.c:3268
__console_flush_and_unlock kernel/printk/printk.c:3298 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3338
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline]
m920x_rc_query+0x2f6/0x830 drivers/media/usb/dvb-usb/m920x.c:-1
legacy_dvb_usb_read_remote_control+0x100/0x470 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
process_one_work+0x94a/0x15d0 kernel/workqueue.c:3267
process_scheduled_works kernel/workqueue.c:3350 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3431
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245