INFO: task syz.1.300:6729 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.300 state:D stack:28776 pid:6729 tgid:6727 ppid:5592 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821
write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe94359e0d9
RSP: 002b:00007fe944460028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe943825fa0 RCX: 00007fe94359e0d9
RDX: 0000000000000055 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007fe943635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe943826038 R14: 00007fe943825fa0 R15: 00007fffeec497a8
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/5352:
#0: ffff8880335980a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
5 locks held by kworker/0:4/5687:
3 locks held by syz.2.263/6630:
#0: ffff88807ee800f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888035842450 (sb_writers#16){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2:
ffffffff8f0724c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
3 locks held by syz.1.300/6729:
#0: ffff88802cc9deb0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888035b5a450 (sb_writers#16){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f0724c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
2 locks held by syz.5.723/7827:
#0: ffff8880726c80d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880726c80d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880726c80d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff8880726c80d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f0724c0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
1 lock held by syz.6.1235/9235:
1 lock held by cxacru/9249:
#0: ffffffff8ea8d3a8 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xab/0x250 kernel/umh.c:214
2 locks held by syz.0.1242/9259:
#0: ffff88807973a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffff88807973a128 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:939 [inline]
#1: ffff88807973a128 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:958 [inline]
#1: ffff88807973a128 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write.isra.0+0x24b/0x890 drivers/tty/tty_io.c:1081
2 locks held by syz.0.1242/9261:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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: 9261 Comm: syz.0.1242 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:__lock_release kernel/locking/lockdep.c:5546 [inline]
RIP: 0010:lock_release kernel/locking/lockdep.c:5889 [inline]
RIP: 0010:lock_release+0xf4/0x310 kernel/locking/lockdep.c:5875
Code: 4c 24 0c 44 89 fa 48 89 de 4c 89 e7 e8 f5 85 ff ff 48 85 c0 0f 84 88 01 00 00 8b 50 24 85 d2 0f 85 de 01 00 00 66 83 78 22 1f <76> 0c 66 83 68 22 20 66 83 78 22 1f 77 62 8b 54 24 0c 41 89 94 24
RSP: 0018:ffffc900101a6280 EFLAGS: 00000093
RAX: ffff88807d423130 RBX: ffffffff8ebe8200 RCX: ffffc900101a628c
RDX: 0000000000000000 RSI: ffffffff8ebe8200 RDI: ffff88807d423130
RBP: ffffffff81b876be R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000016c76 R12: ffff88807d422540
R13: ffffc900101a6338 R14: 0000000000000202 R15: 0000000000000003
FS: 00007f691bbb66c0(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f0d7ef2f8 CR3: 00000000805cf000 CR4: 00000000003526f0
Call Trace:
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x162/0x1e0 mm/page_owner.c:165
__set_page_owner+0x8c/0x540 mm/page_owner.c:341
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490
folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509
shmem_alloc_folio+0x135/0x160 mm/shmem.c:1917
shmem_alloc_and_add_folio+0x371/0xd40 mm/shmem.c:1959
shmem_get_folio_gfp+0x6ad/0x1910 mm/shmem.c:2512
shmem_get_folio mm/shmem.c:2618 [inline]
shmem_write_begin+0x1a4/0x420 mm/shmem.c:3249
generic_perform_write+0x292/0xa40 mm/filemap.c:4364
shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3424
__kernel_write_iter+0x2ac/0x930 fs/read_write.c:621
dump_emit_page fs/coredump.c:1298 [inline]
dump_user_range+0x3f9/0xad0 fs/coredump.c:1372
elf_core_dump+0x2d68/0x3d20 fs/binfmt_elf.c:2109
coredump_write fs/coredump.c:1052 [inline]
do_coredump fs/coredump.c:1131 [inline]
vfs_coredump+0x294b/0x56f0 fs/coredump.c:1200
get_signal+0x1f2a/0x21e0 kernel/signal.c:3031
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
irqentry_exit+0x402/0xa00 kernel/entry/common.c:165
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x7f691ad9e0e1
Code: 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 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:0000000000000030 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f691b026090 RCX: 00007f691ad9e0d9
RDX: 0000000000000000 RSI: 0000000000000030 RDI: 0000000000000600
RBP: 00007f691ae35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f691b026128 R14: 00007f691b026090 R15: 00007fff8f27f2f8