INFO: task syz.2.826:8516 blocked for more than 143 seconds.
Tainted: G L Y syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.826 state:D stack:27432 pid:8516 tgid:8513 ppid:5614 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5581 [inline]
__schedule+0x1b47/0x5b40 kernel/sched/core.c:7384
__schedule_loop kernel/sched/core.c:7461 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7476
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7533
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
write_threads+0x3b1/0x610 fs/nfsd/nfsctl.c:439
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:117
vfs_write+0x296/0xba0 fs/read_write.c:685
ksys_write+0x150/0x270 fs/read_write.c:739
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: 0033:0x7fccd879e159
RSP: 002b:00007fccd96b5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fccd8a26090 RCX: 00007fccd879e159
RDX: 0000000000000001 RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007fccd883506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fccd8a26128 R14: 00007fccd8a26090 R15: 00007ffe4e0ec728
Showing all locks held in the system:
locks held by khungtaskd/33: 1, last CPU#1:
#0: ffffffff8f15c520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8f15c520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8f15c520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5369: 2, on CPU#0:
#0: ffff8880362820a0 (&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 syz-executor/5613: 4, last CPU#1:
#0: ffffffff8f2381b0 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff8f2381b0 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x470 kernel/fork.c:1594
#1: ffff8880345c4cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:548 [inline]
#1: ffff8880345c4cc0 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff8880787d0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:538 [inline]
#2: ffff8880787d0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff8f15c520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8f15c520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8f15c520 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:302
locks held by kworker/1:5/5750: 3, on CPU#1:
#0: ffff88802368a948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88802368a948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88802368a948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff88802368a948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90004947c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004947c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004947c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90004947c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88802a1ec1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802a1ec1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
locks held by syz.2.826/8515: 3, on CPU#1:
#0: ffff888022bb2470 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160 fs/file.c:1408
#1: ffff88807e804460 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88807e804460 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8f49fc80 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:874
locks held by syz.2.826/8516: 3, on CPU#1:
#0: ffff8880744c0ef0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160 fs/file.c:1408
#1: ffff88807e804460 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88807e804460 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8f49fc80 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b1/0x610 fs/nfsd/nfsctl.c:439
locks held by syz.0.1856/12068: 1, on CPU#0:
#0: ffff8880b843c1a0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:678
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: khungtaskd Tainted: G L Y syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND
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:377 [inline]
watchdog+0x1058/0x10d0 kernel/hung_task.c:598
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: 0 Comm: swapper/0 Tainted: G L Y syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 6b a2 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 97 29 00 fb f4 8c 18 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8ee07ca0 EFLAGS: 00000242
RAX: 00000000001ca8ab RBX: ffffffff819ccf00 RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8e74f1c1 RDI: ffffffff8c8f3280
RBP: ffffffff8ee07d78 R08: ffff8880b8433e5b R09: 1ffff110170867cb
R10: dffffc0000000000 R11: ffffed10170867cc R12: 0000000000000000
R13: 1ffffffff1dd1df8 R14: 1ffffffff1dc0f9c R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888124623000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f46d45eb840 CR3: 000000007c380000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000007 DR2: 0000000000000004
DR3: 0000000000000008 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_safe_halt arch/x86/kernel/process.c:767 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:768
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x2e0/0x540 kernel/sched/idle.c:355
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454
rest_init+0x378/0x3a0 init/main.c:729
start_kernel+0x397/0x3e0 init/main.c:1188
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x157