INFO: task syz.1.2304:13583 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2304 state:D stack:26952 pid:13583 ppid:5792 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
sync_bdevs+0x1af/0x330 block/bdev.c:1059
ksys_sync+0xba/0x150 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7d0898ebe9
RSP: 002b:00007f7d09891038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7d08bc6090 RCX: 00007f7d0898ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7d08bc6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7d08bc6128 R14: 00007f7d08bc6090 R15: 00007ffc7e2efb08
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2fc20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
3 locks held by kworker/u4:2/42:
2 locks held by getty/5556:
#0: ffff88802cd130a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by udevd/12377:
#0: ffff888141b4a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788
1 lock held by udevd/12470:
#0: ffff88814130f4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:927
1 lock held by syz.1.2304/13583:
#0: ffff888141b4a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1059
3 locks held by kworker/1:7/14089:
#0: ffff888017870938 (
(wq_completion)events
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:2609 [inline]
, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1:
ffffc900033b7d00
(
free_ipc_work
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:2609 [inline]
, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8cd35bf8 (rcu_state.exp_mutex){+.+.}-{3:3}
, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004
3 locks held by kworker/1:14/14097:
1 lock held by syz-executor/15499:
#0: ffffffff8cd35bf8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#0: ffffffff8cd35bf8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004
6 locks held by syz.0.2901/15539:
1 lock held by syz.0.2901/15542:
#0: ffff88814130f4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788
1 lock held by syz.2.2910/15571:
#0: ffffffff8dfbc488 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dfbc488 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf41/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 15555 Comm: syz.5.2907 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x60 kernel/kcov.c:216
Code: 04 24 65 48 8b 0d 50 2a 7e 7e 65 8b 15 51 2a 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48
RSP: 0018:ffffc900033774e0 EFLAGS: 00000246
RAX: ffffffff813ad8f9 RBX: ffffc90003377af8 RCX: ffff888022ff8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffc90003377af8
RBP: ffffc90003377618 R08: ffff888022ff8000 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc900033775c8
R13: dffffc0000000000 R14: ffffc90003377af8 R15: ffffffff8ece9770
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbf85eda263 CR3: 000000002ced5000 CR4: 00000000003506e0
Call Trace:
__read_once_word_nocheck+0x9/0x10 include/asm-generic/rwonce.h:66
deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline]
unwind_next_frame+0x15f9/0x2970 arch/x86/kernel/unwind_orc.c:585
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf7/0x1f0 mm/page_owner.c:128
__reset_page_owner+0x4e/0x190 mm/page_owner.c:149
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1154 [inline]
free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
vfree+0x1a6/0x320 mm/vmalloc.c:2868
kcov_put kernel/kcov.c:438 [inline]
kcov_close+0x2b/0x50 kernel/kcov.c:534
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1ce/0x250 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0x90b/0x23c0 kernel/exit.c:883
do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
get_signal+0x12fc/0x1400 kernel/signal.c:2902
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1d3d98ebe9
Code: Unable to access opcode bytes at 0x7f1d3d98ebbf.
RSP: 002b:00007f1d3e787038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 000000000000000b RBX: 00007f1d3dbc5fa0 RCX: 00007f1d3d98ebe9
RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007f1d3da11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1d3dbc6038 R14: 00007f1d3dbc5fa0 R15: 00007ffc17e43f38