INFO: task syz.6.2373:13395 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.6.2373 state:D stack:28808 pid:13395 tgid:13391 ppid:7289 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5527 [inline]
__schedule+0x17dd/0x5940 kernel/sched/core.c:7295
__schedule_loop kernel/sched/core.c:7372 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7387
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7444
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
fdget_pos+0x246/0x320 fs/file.c:1259
class_fd_pos_constructor include/linux/file.h:85 [inline]
ksys_write+0x79/0x270 fs/read_write.c:730
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: 0033:0x7f0096f9e159
RSP: 002b:00007f0097e9c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0097226270 RCX: 00007f0096f9e159
RDX: 0000000000000005 RSI: 00002000000000c0 RDI: 0000000000000007
RBP: 00007f009703506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0097226308 R14: 00007f0097226270 R15: 00007ffc733ef248
INFO: task syz.6.2373:13396 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.6.2373 state:D stack:27432 pid:13396 tgid:13391 ppid:7289 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5527 [inline]
__schedule+0x17dd/0x5940 kernel/sched/core.c:7295
__schedule_loop kernel/sched/core.c:7372 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7387
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7444
__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:438
nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:116
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: 0033:0x7f0096f9e159
RSP: 002b:00007f0097e7b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0097226360 RCX: 00007f0096f9e159
RDX: 0000000000000001 RSI: 0000200000000140 RDI: 0000000000000008
RBP: 00007f009703506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f00972263f8 R14: 00007f0097226360 R15: 00007ffc733ef248
Showing all locks held in the system:
locks held by kworker/0:0/9: 3, on CPU#0:
#0: ffff88813ff43140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813ff43140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813ff43140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3364 [inline]
#0: ffff88813ff43140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3482
#1: ffffc900000e7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900000e7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900000e7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3364 [inline]
#1: ffffc900000e7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3482
#2: ffff888032a82250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1fd/0x3b0 drivers/net/netdevsim/fib.c:1490
locks held by khungtaskd/32: 1, last CPU#0:
#0: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5367: 2, on CPU#0:
#0: ffff8880362d30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/5598: 2, last CPU#0:
#0: ffff8880338b5038 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:586 [inline]
#0: ffff8880338b5038 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.6.2373/13394: 3, on CPU#0:
#0: ffff888079a79970 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888029234460 (sb_writers#16){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888029234460 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8f2a0020 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:869
locks held by syz.6.2373/13395: 1, on CPU#0:
#0: ffff888079a79970 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
locks held by syz.6.2373/13396: 3, on CPU#0:
#0: ffff88805b48cb70 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888029234460 (sb_writers#16){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888029234460 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffffffff8f2a0020 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b1/0x610 fs/nfsd/nfsctl.c:438
locks held by syz-executor/13637: 2, on CPU#0:
#0: ffff8880365b20e8 (&type->s_umount_key#64){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff8880365b20e8 (&type->s_umount_key#64){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff8880365b20e8 (&type->s_umount_key#64){+.+.}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:617
#1: ffffffff8f2a0020 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:590
locks held by kworker/u8:15/14195: 2, on CPU#0:
#0: ffff88813fe04140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe04140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe04140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3364 [inline]
#0: ffff88813fe04140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3482
#1: ffffc9000371fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000371fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000371fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3364 [inline]
#1: ffffc9000371fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3482
locks held by syz.8.3472/16630: 2, last CPU#0:
#0: ffff88802a505cf8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:586 [inline]
#0: ffff88802a505cf8 (&mm->mmap_lock){++++}-{4:4}, at: do_pages_stat_array mm/migrate.c:2462 [inline]
#0: ffff88802a505cf8 (&mm->mmap_lock){++++}-{4:4}, at: do_pages_stat mm/migrate.c:2541 [inline]
#0: ffff88802a505cf8 (&mm->mmap_lock){++++}-{4:4}, at: kernel_move_pages mm/migrate.c:2627 [inline]
#0: ffff88802a505cf8 (&mm->mmap_lock){++++}-{4:4}, at: __do_sys_move_pages mm/migrate.c:2638 [inline]
#0: ffff88802a505cf8 (&mm->mmap_lock){++++}-{4:4}, at: __se_sys_move_pages+0x149d/0x1c80 mm/migrate.c:2633
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ef5c7a0 (rcu_read_lock){....}-{1:3}, at: mtree_load+0x12a/0x780 lib/maple_tree.c:5809
locks held by syz.5.3510/16793: 1, last CPU#0:
#0: ffff888057999e20 (&sb->s_type->i_mutex_key#9/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
#0: ffff888057999e20 (&sb->s_type->i_mutex_key#9/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x19a/0x520 fs/libfs.c:619
locks held by sed/16801: 1, last CPU#0:
#0: ffff88802a501d38 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:548 [inline]
#0: ffff88802a501d38 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1dd/0x4e0 mm/util.c:579
locks held by modprobe/16803: 1, last CPU#0:
#0: ffff88802a501078 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:548 [inline]
#0: ffff88802a501078 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1dd/0x4e0 mm/util.c:579
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
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