INFO: task syz.2.6475:3400 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.6475 state:D stack:25656 pid:3400 tgid:3399 ppid:1703 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x17dd/0x5820 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7474
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7531
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
nfsd_nl_expkey_set_reqs_doit+0xfe/0xaf0 fs/nfsd/export.c:561
genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2576
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x7f0/0xb20 net/netlink/af_netlink.c:1920
sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800
__sock_sendmsg net/socket.c:818 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2715
___sys_sendmsg+0x2a5/0x360 net/socket.c:2769
__sys_sendmsg net/socket.c:2801 [inline]
__do_sys_sendmsg net/socket.c:2806 [inline]
__se_sys_sendmsg net/socket.c:2804 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff05b39f559
RSP: 002b:00007ff05c32b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff05b625fa0 RCX: 00007ff05b39f559
RDX: 0000000000000020 RSI: 00002000000003c0 RDI: 000000000000000a
RBP: 00007ff05b436b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff05b626038 R14: 00007ff05b625fa0 R15: 00007ffec366c628
Showing all locks held in the system:
locks held by khungtaskd/33: 1, last CPU#1:
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5393: 2, on CPU#0:
#0: ffff8880338590a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032432e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz.0.6299/2210: 2, on CPU#1:
#0: ffffffff912db128 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff9009e720 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz-executor/3107: 1, last CPU#1:
#0: ffff888075b3cd00 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff888075b3cd00 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:734
locks held by syz.2.6475/3400: 2, on CPU#1:
#0: ffffffff912db128 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff9009e720 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_expkey_set_reqs_doit+0xfe/0xaf0 fs/nfsd/export.c:561
locks held by syz-executor/4990: 4, last CPU#1:
#0: ffffffff8fe33fd0 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
#0: ffffffff8fe33fd0 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x470 kernel/fork.c:1595
#1: ffff88807875f180 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#1: ffff88807875f180 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff888032250340 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
#2: ffff888032250340 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.0.6940/6366: 2, last CPU#0:
#0: ffff8880476eed08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
#1: ffff888075451bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock+0x1f/0x70 include/linux/mmap_lock.h:619
locks held by syz.0.6940/6368: 5, last CPU#1:
#0: ffff88804a17f270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160 fs/file.c:1408
#1: ffff888033b6a460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2758 [inline]
#1: ffff888033b6a460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88802bea5d00 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88802bea5d00 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3433
#3: ffff888075451bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:619 [inline]
#3: ffff888075451bc0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#3: ffff888075451bc0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: count_memcg_events_mm include/linux/memcontrol.h:990 [inline]
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: count_memcg_event_mm+0x21/0x260 include/linux/memcontrol.h:1000
locks held by syz.0.6940/6373: 2, on CPU#1:
#0: ffff888033b6a460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2758 [inline]
#0: ffff888033b6a460 (sb_writers#5){.+.+}-{0:0}, at: vfs_fallocate+0x5e0/0x7e0 fs/open.c:337
#1: ffff88802bea5d00 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#1: ffff88802bea5d00 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_fallocate+0x17c/0xf10 mm/shmem.c:3640
locks held by syz.0.6940/6377: 5, last CPU#0:
#0: ffff888049138260 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1717 [inline]
#0: ffff888049138260 (sk_lock-AF_INET){+.+.}-{0:0}, at: l2tp_ip_sendmsg+0x34/0x1630 net/l2tp/l2tp_ip.c:433
#1: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: l2tp_ip_sendmsg+0x435/0x1630 net/l2tp/l2tp_ip.c:488
#2: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#2: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: __ip_queue_xmit+0x65/0x1b10 net/ipv4/ip_output.c:476
#3: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450 net/ipv4/ip_output.c:432
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#4: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3de/0x10b0 net/ipv4/ip_output.c:229
locks held by syz.0.6940/6381: 2, last CPU#0:
#0: ffffffff91276f20 (rtnl_mutex){+.+.}-{4:4}, at: do_ip_setsockopt+0xe95/0x2e30 net/ipv4/ip_sockglue.c:1077
#1: ffff888049138260 (sk_lock-AF_INET){+.+.}-{0:0}, at: do_ip_setsockopt+0x1556/0x2e30 net/ipv4/ip_sockglue.c:1078
locks held by sed/6374: 1, last CPU#1:
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#0: ffffffff8fd59ca0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0xfd2/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x480 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: 27498 Comm: kworker/u8:115 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline]
RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline]
RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:208
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc 89 f6 31 d2 e9 66 53 aa 03 66 0f 1f 44 00
RSP: 0018:ffffc90000007e50 EFLAGS: 00000046
RAX: 000000000000000f RBX: ffff8880b8423f40 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 000000000000000f RDI: 0000000000000838
RBP: ffffc90000007f10 R08: 0000000000000100 R09: 0000000000000001
R10: 0000000000000003 R11: ffffffff8175b510 R12: ffffffff8175b510
R13: 1ffff110170847f1 R14: 0000000000000000 R15: ffff8880b8423f8c
FS: 0000000000000000(0000) GS:ffff888123a6b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff97b5f5c38 CR3: 0000000086246000 CR4: 00000000003526f0
Call Trace:
apic_write arch/x86/include/asm/apic.h:405 [inline]
lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:418
clockevents_program_event+0x44e/0x630 kernel/time/clockevents.c:381
hrtimer_update_softirq_timer kernel/time/hrtimer.c:1344 [inline]
hrtimer_run_softirq+0x255/0x2e0 kernel/time/hrtimer.c:2152
handle_softirqs+0x265/0x8d0 kernel/softirq.c:669
do_softirq+0x77/0xd0 kernel/softirq.c:569
__local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
local_bh_enable include/linux/bottom_half.h:33 [inline]
__alloc_skb+0x1b1/0x7a0 net/core/skbuff.c:700
alloc_skb include/linux/skbuff.h:1390 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:744 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:801 [inline]
nsim_dev_trap_report_work+0x25f/0xb30 drivers/net/netdevsim/dev.c:847
process_one_work kernel/workqueue.c:3495 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
kthread+0x38b/0x480 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