INFO: task syz.6.2879:14288 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.2879      state:D stack:25008 pid:14288 ppid:  9221 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 perf_pending_task_sync+0x13c/0x1c0 kernel/events/core.c:5127
 _free_event+0x34/0xe30 kernel/events/core.c:5133
 put_event kernel/events/core.c:5258 [inline]
 perf_event_release_kernel+0x7c4/0x850 kernel/events/core.c:5383
 perf_release+0x37/0x40 kernel/events/core.c:5393
 __fput+0x212/0x8c0 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x635/0x2110 kernel/exit.c:884
 do_group_exit+0x12c/0x2f0 kernel/exit.c:998
 get_signal+0x7eb/0x12e0 kernel/signal.c:2901
 arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd767ba0e59
RSP: 002b:00007fd765df90e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fd767e28fa8 RCX: 00007fd767ba0e59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd767e28fa8
RBP: 00007fd767e28fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd767e29038 R14: 00007ffd6f206170 R15: 00007ffd6f206258
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by udevd/3561:
2 locks held by getty/3947:
 #0: ffff88802c735098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:18/4421:
3 locks held by kworker/1:7/13638:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000301fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8c3238b0 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043
2 locks held by syz.9.3307/16040:
4 locks held by kworker/u4:1/16962:
4 locks held by syz.1.3613/17383:
3 locks held by syz.1.3613/17391:
1 lock held by syz.1.3613/17400:
 #0: ffffffff8ccde1e8 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1a70 drivers/net/ppp/ppp_generic.c:738

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 17383 Comm: syz.1.3613 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_acquire+0xe08/0x7b50 kernel/locking/lockdep.c:4985
Code: fc ff df 48 63 c3 48 0f a3 05 84 a5 c1 0e 0f 83 5d 4c 00 00 49 8d 9d e0 0a 00 00 48 89 d8 48 c1 e8 03 48 89 84 24 98 00 00 00 <42> 80 3c 00 00 74 12 48 89 df e8 69 27 61 00 49 b8 00 00 00 00 00
RSP: 0018:ffffc90000dd0400 EFLAGS: 00000806
RAX: 1ffff1100f9758cc RBX: ffff88807cbac660 RCX: ffffffff815ceb27
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901e90c8
RBP: ffffc90000dd0630 R08: dffffc0000000000 R09: 1ffffffff203d219
R10: dffffc0000000000 R11: fffffbfff203d21a R12: ffff88807cbac708
R13: ffff88807cbabb80 R14: 0000000000000003 R15: ffff88807cbac6e8
FS:  00007f54674176c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb998de0dac CR3: 00000000642dc000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 seqcount_lockdep_reader_access+0xcd/0x1d0 include/linux/seqlock.h:103
 timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:388 [inline]
 ktime_get+0x7b/0x270 kernel/time/timekeeping.c:831
 hrtimer_forward_now include/linux/hrtimer.h:508 [inline]
 perf_swevent_hrtimer+0x455/0x550 kernel/events/core.c:10939
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:ffs arch/x86/include/asm/bitops.h:297 [inline]
RIP: 0010:handle_softirqs+0x1a4/0x830 kernel/softirq.c:564
Code: 24 78 44 89 64 24 30 0f b7 db 48 c7 c7 e0 13 2a 8a e8 30 fc 75 08 65 66 c7 05 86 6d ba 7e 00 00 e8 01 ef 35 00 fb 89 5c 24 3c <b8> ff ff ff ff 0f bc 44 24 3c 41 89 c6 41 ff c6 0f 85 d2 00 00 00
RSP: 0018:ffffc90000dd0e20 EFLAGS: 00000282
RAX: d99a4e1bafca2900 RBX: 00000000000003c2 RCX: d99a4e1bafca2900
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a2840
RBP: ffffc90000dd0f30 R08: ffffffff901e90c7 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: 000000000000000a
R13: 0000000000000000 R14: ffff88807cbabb80 R15: dffffc0000000000
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:console_unlock+0xc90/0x10f0 kernel/printk/printk.c:2749
Code: 75 11 e8 83 d7 18 00 4d 85 e4 75 16 e8 79 d7 18 00 eb 15 e8 72 d7 18 00 e8 4d fb 5e 08 4d 85 e4 74 ea e8 63 d7 18 00 fb 31 ff <89> de e8 b9 da 18 00 85 db 0f 94 c0 22 44 24 1f 3c 01 75 1f e8 47
RSP: 0018:ffffc900034f6a20 EFLAGS: 00000246
RAX: ffffffff81601b3d RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90011574000 RSI: 000000000000a61f RDI: 0000000000000000
RBP: ffffc900034f6c90 R08: ffffffff901e90c7 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: 0000000000000200
R13: 0000000000000067 R14: 0000000000000000 R15: dffffc0000000000
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 __nla_validate_parse+0x1f64/0x27b0 lib/nlattr.c:625
 __nla_parse+0x3c/0x50 lib/nlattr.c:710
 __nlmsg_parse include/net/netlink.h:744 [inline]
 nlmsg_parse_deprecated include/net/netlink.h:783 [inline]
 nl80211_prepare_wdev_dump+0x396/0x690 net/wireless/nl80211.c:949
 nl80211_dump_survey+0x194/0x1300 net/wireless/nl80211.c:9677
 netlink_dump+0x675/0xcd0 net/netlink/af_netlink.c:2288
 __netlink_dump_start+0x518/0x700 net/netlink/af_netlink.c:2391
 genl_family_rcv_msg_dumpit net/netlink/genetlink.c:689 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:772 [inline]
 genl_rcv_msg+0xbc7/0xfa0 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2512
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1923
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
 __sys_sendmsg net/socket.c:2529 [inline]
 __do_sys_sendmsg net/socket.c:2538 [inline]
 __se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f54691bee59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5467417028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5469446fa0 RCX: 00007f54691bee59
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000008
RBP: 00007f5469254e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5469447038 R14: 00007f5469446fa0 R15: 00007ffe6e9d25c8
 </TASK>