INFO: task syz.0.17:6461 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17 state:D stack:26904 pid:6461 tgid:6460 ppid:6360 task_flags:0x400040 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4c90 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x704/0x14d0 kernel/locking/mutex.c:760
sync_bdevs+0x1ac/0x340 block/bdev.c:1288
ksys_sync+0xb9/0x150 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x8a/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fc94dd8efc9
RSP: 002b:00007fc94ec24038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fc94dfe5fa0 RCX: 00007fc94dd8efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fc94dfe5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc94dfe6038 R14: 00007fc94dfe5fa0 R15: 00007ffd40dc5028
INFO: task syz.0.17:6461 is blocked on a mutex likely owned by task udevd:6206.
task:udevd state:D stack:20680 pid:6206 tgid:6206 ppid:5189 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4c90 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
io_schedule+0x81/0xe0 kernel/sched/core.c:7871
folio_wait_bit_common+0x7a9/0xb80 mm/filemap.c:1330
folio_wait_bit_killable mm/filemap.c:1475 [inline]
folio_wait_locked_killable include/linux/pagemap.h:1223 [inline]
filemap_read_folio+0x203/0x370 mm/filemap.c:2450
do_read_cache_folio+0x350/0x590 mm/filemap.c:4024
read_mapping_folio include/linux/pagemap.h:999 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:722
adfspart_check_ICS+0xa4/0xa50 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x75d/0x14b0 block/partitions/core.c:693
blkdev_get_whole+0x380/0x510 block/bdev.c:748
bdev_open+0x318/0xe80 block/bdev.c:957
blkdev_open+0x457/0x600 block/fops.c:701
do_dentry_open+0x951/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ee1/0x3830 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x8a/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f328bea7407
RSP: 002b:00007ffcea104dc0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f328c566880 RCX: 00007f328bea7407
RDX: 00000000000a0800 RSI: 000056460d32aa50 RDI: ffffffffffffff9c
RBP: 000056460d311910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000056460d338b60
R13: 000056460d31f190 R14: 0000000000000000 R15: 000056460d338b60
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8dd3d360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8dd3d360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8dd3d360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:2/51:
#0: ffff8880b893a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
#1: ffff8880b8924048 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline]
#1: ffff8880b8924048 (psi_seq){-.-.}-{0:0}, at: __schedule+0x22c6/0x4c90 kernel/sched/core.c:6923
#2: ffff8880b8924048 (psi_seq){-.-.}-{0:0}, at: psi_enqueue kernel/sched/stats.h:166 [inline]
#2: ffff8880b8924048 (psi_seq){-.-.}-{0:0}, at: enqueue_task+0x33d/0x410 kernel/sched/core.c:2094
2 locks held by getty/5583:
#0: ffff888032e190a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/0:5/5878:
#0: ffff88813fe59948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813fe59948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1790 kernel/workqueue.c:3346
#1: ffffc900041cfb80 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc900041cfb80 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1790 kernel/workqueue.c:3346
#2: ffff88802f658240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1f7/0x3b0 drivers/net/netdevsim/fib.c:1490
1 lock held by udevd/6179:
#0: ffff8880249fd358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by udevd/6206:
#0: ffff8880249f9358 (&disk->open_mutex){+.+.}-{4:4}
, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by udevd/6367:
#0: ffff888024a3b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.0.17/6461:
#0: ffff8880249f9358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by syz.1.18/6483:
#0: ffff8880249f9358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by udevd/6488:
#0: ffff8880249ff358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.2.19/6506:
#0: ffff888024a3b358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by syz.3.20/6534:
#0: ffff8880249fd358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by udevd/6540:
#0: ffff888142f31358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.4.21/6564:
#0: ffff8880249ff358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by udevd/6569:
#0: ffff888142f33358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.5.22/6593:
#0: ffff888142f31358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by udevd/6598:
#0: ffff888025043358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by udevd/6599:
#0: ffff888142f35358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.6.23/6623:
#0: ffff888142f33358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by udevd/6634:
#0: ffff888142f37358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.7.24/6658:
#0: ffff888142f35358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by udevd/6663:
#0: ffff888025041358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xda/0xe80 block/bdev.c:945
1 lock held by syz.8.25/6687:
#0: ffff888142f37358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by syz.9.26/6716:
#0: ffff888025041358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
=============================================
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:332 [inline]
watchdog+0x16fb/0x1740 kernel/hung_task.c:495
kthread+0x711/0x890 kernel/kthread.c:463
ret_from_fork+0x4b8/0x860 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: 5884 Comm: kworker/u9:2 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: hci9 hci_cmd_timeout
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:407
Code: 7e ab fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 fc 43 11 fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc9000412f2d0 EFLAGS: 00000002
RAX: 0000000000000033 RBX: 0000000000000033 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff888141f18237 R09: 1ffff110283e3046
R10: dffffc0000000000 R11: ffffffff85141630 R12: dffffc0000000000
R13: ffffffff995268ea R14: ffffffff99838400 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881263ee000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa92a174960 CR3: 000000007bc2a000 CR4: 00000000003526f0
Call Trace:
serial_port_out include/linux/serial_core.h:811 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x140c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3111 [inline]
console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
bt_err+0x10b/0x160 net/bluetooth/lib.c:296
hci_cmd_timeout+0xff/0x1e0 net/bluetooth/hci_core.c:1473
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x1790 kernel/workqueue.c:3346
worker_thread+0xa57/0xfc0 kernel/workqueue.c:3427
kthread+0x711/0x890 kernel/kthread.c:463
ret_from_fork+0x4b8/0x860 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245