INFO: task syz.3.8891:29753 blocked for m
INFO: task syz.3.8891:29753 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.8891 state:D stack:26784 pid:29753 tgid:29739 ppid:5615 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5520 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7270
__schedule_loop kernel/sched/core.c:7347 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7362
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
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:2556
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2713
___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
__sys_sendmsg net/socket.c:2799 [inline]
__do_sys_sendmsg net/socket.c:2804 [inline]
__se_sys_sendmsg net/socket.c:2802 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
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: 0033:0x7fbb3c99e159
RSP: 002b:00007fbb3d8af028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbb3cc26180 RCX: 00007fbb3c99e159
RDX: 0000000004040080 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007fbb3ca3503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbb3cc26218 R14: 00007fbb3cc26180 R15: 00007ffc95036f28
Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#0:
#0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
#0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline]
#0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
#1: ffffffff9ad32098 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline]
#1: ffffffff9ad32098 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413
locks held by khungtaskd/31: 1, last CPU#1:
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6837
locks held by udevd/4981: 2, last CPU#1:
#0: ffffffff8f4ef978 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
#0: ffffffff8f4ef978 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:305 [inline]
#0: ffffffff8f4ef978 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock security/tomoyo/common.h:1112 [inline]
#0: ffffffff8f4ef978 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_check_open_permission+0x1d3/0x470 security/tomoyo/file.c:772
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by getty/5369: 2, on CPU#1:
#0: ffff888035c1d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/u8:18/13955: 2, on CPU#0:
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc900035f7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900035f7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900035f7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc900035f7c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by udevd/29069: 1, on CPU#1:
#0: ffff888026add350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by udevd/29078: 1, on CPU#1:
#0: ffff888026a71350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz.3.8891/29745: 2, on CPU#0:
#0: ffffffff902c1be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz.3.8891/29753: 2, on CPU#0:
#0: ffffffff902c1be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz.2.9017/30172: 2, on CPU#0:
#0: ffffffff902c1be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_cache_flush_doit+0xb5/0x1b0 fs/nfsd/nfsctl.c:2319
locks held by syz.6.9906/668: 2, on CPU#1:
#0: ffffffff902c1be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8f09e400 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_cache_flush_doit+0xe2/0x1b0 fs/nfsd/nfsctl.c:2319
locks held by syz-executor/1269: 4, last CPU#1:
#0: ffffffff8ee35c10 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
#0: ffffffff8ee35c10 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1595
#1: ffff88807f0436b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#1: ffff88807f0436b8 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff8880777a03b8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
#2: ffff8880777a03b8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.5.10591/2997: 2, last CPU#1:
#0: ffff8880318db6b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff8880318db6b8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.1.10596/3011: 1, last CPU#1:
#0: ffff888042daba88 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
locks held by modprobe/3014: 1, last CPU#0:
#0: ffff88807c1fb6b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:619 [inline]
#0: ffff88807c1fb6b8 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#0: ffff88807c1fb6b8 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0xfd7/0x1030 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: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:416
Code: b2 55 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 cc 7b c5 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 c7 0f 75 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000157900 EFLAGS: 00000002
RAX: 0000000000000066 RBX: 0000000000000066 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85720850 R12: dffffc0000000000
R13: 0000000000000066 R14: ffffffff9ad320c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124cd9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564e07ebe008 CR3: 000000003d404000 CR4: 00000000003526f0
Call Trace:
serial_port_out include/linux/serial_core.h:817 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3287 [inline]
__serial8250_console_fifo_write+0x1e6/0x3e0 drivers/tty/serial/8250/8250_port.c:3359
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
serial8250_console_write+0xaa1/0x1200 drivers/tty/serial/8250/8250_port.c:3493
nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271
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