INFO: task syz.4.2882:12409 blocked for more than 143 sec[ 480.399458][ T39] INFO: task syz.4.2882:12409 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.4.2882 state:D stack:25560 pid:12409 tgid:12408 ppid:10291 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5402 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7204
__schedule_loop kernel/sched/core.c:7283 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7298
cgroup_lock_and_drain_offline+0x516/0x650 kernel/cgroup/cgroup.c:3248
cgroup_kn_lock_live+0x120/0x230 kernel/cgroup/cgroup.c:1699
cgroup_subtree_control_write+0x4b3/0x10a0 kernel/cgroup/cgroup.c:3550
cgroup_file_write+0x331/0x8f0 kernel/cgroup/cgroup.c:4289
kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x629/0xba0 fs/read_write.c:688
ksys_write+0x156/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f836358ce59
RSP: 002b:00007f83617e6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8363805fa0 RCX: 00007f836358ce59
RDX: 0000000000000005 RSI: 0000200000000300 RDI: 0000000000000008
RBP: 00007f8363622d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8363806038 R14: 00007f8363805fa0 R15: 00007ffd6cce3678
Showing all locks held in the system:
1 lock held by khungtaskd/39:
#0: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777
2 locks held by getty/5370:
#0: ffff8880366a60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
9 locks held by syz-executor/5620:
#0: ffffffff8e29d1f0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff8e29d1f0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1594
#1: ffff888031f72cb0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
#1: ffff888031f72cb0 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x184/0x1d70 mm/mmap.c:1739
#2: ffff88803fd462b0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
#2: ffff88803fd462b0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x272/0x1d70 mm/mmap.c:1746
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#4: ffff88803818a7d8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#4: ffff88803818a7d8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#7: ffff888054500598 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1272 [inline]
#7: ffff888054500598 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range+0x5ae/0x5550 mm/memory.c:1408
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock_nested+0x1de/0x3f0 kernel/locking/spinlock_rt.c:65
3 locks held by kworker/1:6/5792:
#0: ffff88813fe12538 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293
#1: ffffc9000558fc40 ((gc_work).work){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294
#2: ffffffff8ecdffb8 ("ratelimiter_table_lock"){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffffffff8ecdffb8 ("ratelimiter_table_lock"){+.+.}-{3:3}, at: wg_ratelimiter_gc_entries+0x5d/0x480 drivers/net/wireguard/ratelimiter.c:63
10 locks held by syz-executor/7625:
#0: ffffffff8e29d1f0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff8e29d1f0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1594
#1: ffff88802e81ba30 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
#1: ffff88802e81ba30 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x184/0x1d70 mm/mmap.c:1739
#2: ffff888011f0e2b0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
#2: ffff888011f0e2b0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x272/0x1d70 mm/mmap.c:1746
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#4: ffff88802647fad8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#4: ffff88802647fad8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#7: ffff88802a1d2298 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1272 [inline]
#7: ffff88802a1d2298 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range+0x5ae/0x5550 mm/memory.c:1408
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#8: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock_nested+0x1de/0x3f0 kernel/locking/spinlock_rt.c:65
#9: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#9: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#9: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: page_table_check_set+0x126/0x510 mm/page_table_check.c:112
3 locks held by syz.4.2882/12409:
#0: ffff8880366f1928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1260
#1: ffff888036040480 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
#1: ffff888036040480 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#2: ffff88805a5fb878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
5 locks held by syz.5.5944/18987:
#0: ffff888011f09f30 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
#0: ffff888011f09f30 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x194/0x9e0 mm/mmap.c:1284
#1: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#2: ffff88802bc7b118 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88802bc7b118 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#4: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: page_table_check_clear+0x124/0x4f0 mm/page_table_check.c:77
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:119
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [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:353 [inline]
watchdog+0xfd3/0x1030 kernel/hung_task.c:561
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 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 9e 92 7a 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 6f 16 e5 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff33bf400 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99dfa350 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff854b1e60 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99dfa0c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125c94000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f70f54356b8 CR3: 0000000036f58000 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:1975
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3212 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3277 [inline]
serial8250_console_write+0x11c9/0x1b90 drivers/tty/serial/8250/8250_port.c:3362
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