INFO: task syz.4.4546:22972 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.4546 state:D stack:27984 pid:22972 tgid:22971 ppid:15590 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
cgroup_lock_and_drain_offline+0x383/0x800 kernel/cgroup/cgroup.c:3275
cgroup_kn_lock_live+0x188/0x520 kernel/cgroup/cgroup.c:1715
cgroup_subtree_control_write+0x3dd/0xe90 kernel/cgroup/cgroup.c:3577
cgroup_file_write+0x1e6/0x8a0 kernel/cgroup/cgroup.c:4316
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f89d879de99
RSP: 002b:00007f89d96a4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f89d8a25fa0 RCX: 00007f89d879de99
RDX: 0000000000000005 RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007f89d8833eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f89d8a26038 R14: 00007f89d8a25fa0 R15: 00007ffea4cc3278
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8ebe6180 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe6180 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe6180 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
1 lock held by udevd/4976:
2 locks held by getty/5365:
#0: ffff8880379d70a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
2 locks held by kworker/1:5/5726:
#0: ffff88801bc0b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000431fd08 ((work_completion)(&m->mpeg_thread)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
5 locks held by kworker/u8:25/7195:
2 locks held by syz-executor/18615:
3 locks held by syz.4.4546/22972:
#0: ffff88807c831eb0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88807c4a4450 (sb_writers#10){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffff8880273b1c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 18615 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:__lock_acquire+0x5e5/0x1a40 kernel/locking/lockdep.c:5234
Code: 85 c0 74 dc 8b 0d eb 15 3d 0f 85 c9 75 3d 45 85 ed 0f 85 b0 07 00 00 0f b7 43 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 4b ec 84 14 <0f> 83 ea 0a 00 00 48 8d 04 80 48 8d 04 80 48 8d 04 c5 e0 4d 6a 96
RSP: 0018:ffffc90002f4f1c8 EFLAGS: 00000003
RAX: 0000000000000007 RBX: ffff88807affd648 RCX: 0000000000000000
RDX: 00000000931e622e RSI: 00000000107e9af6 RDI: 00000000698a3efa
RBP: ffff88807affca80 R08: 00000000ff13d9af R09: 0000000000000007
R10: 0000000000000000 R11: 0000000000000000 R12: f0c80db83a12be2a
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
FS: 000055555d16d500(0000) GS:ffff888123ee8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f34d9fecc38 CR3: 0000000073c60000 CR4: 00000000003526f0
Call Trace:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x162/0x1e0 mm/page_owner.c:165
__reset_page_owner+0x84/0x190 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
free_unref_folios+0xa44/0x1710 mm/page_alloc.c:3011
folios_put_refs+0x585/0xaa0 mm/swap.c:1057
folio_batch_release include/linux/folio_batch.h:101 [inline]
shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1149
shmem_truncate_range mm/shmem.c:1277 [inline]
shmem_evict_inode+0x3a5/0xbe0 mm/shmem.c:1407
evict+0x3c2/0xad0 fs/inode.c:825
iput_final fs/inode.c:2019 [inline]
iput.part.0+0x989/0x1050 fs/inode.c:2068
iput+0x35/0x40 fs/inode.c:2034
filename_unlinkat+0x466/0x730 fs/namei.c:5589
__do_sys_unlink fs/namei.c:5620 [inline]
__se_sys_unlink fs/namei.c:5617 [inline]
__x64_sys_unlink+0x46/0x70 fs/namei.c:5617
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbf2cb9cf87
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc47734068 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbf2cb9cf87
RDX: 00007ffc47734090 RSI: 00007ffc47734120 RDI: 00007ffc47734120
RBP: 00007ffc47734120 R08: 00007ffc47735120 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc477351b0
R13: 00007fbf2cc3330a R14: 00000000001651e5 R15: 00007ffc477351f0