INFO: task syz.1.1904:14921 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1904 state:D stack:27624 pid:14921 tgid:14900 ppid:5843 task_flags:0x400140 flags:0x00024004
Call Trace:
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:747
nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1629
genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2534
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg net/socket.c:727 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2566
___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
__sys_sendmsg+0x16d/0x220 net/socket.c:2652
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f168d18e929
RSP: 002b:00007f168e032038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f168d3b6240 RCX: 00007f168d18e929
RDX: 0000000000004000 RSI: 0000200000000480 RDI: 0000000000000005
RBP: 00007f168d210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f168d3b6240 R15: 00007fff098cda58
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e5c47c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5c47c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e5c47c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770
2 locks held by kworker/1:4/5884:
#0: ffff88801b880d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc900042afd10 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
2 locks held by kworker/u10:0/8015:
#0: ffff88801db46948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc9000f57fd10 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
2 locks held by kworker/u10:15/10415:
#0: ffff88801db46948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc9000bcc7d10 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
2 locks held by syz-executor/10748:
#0: ffff88802864e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88802864e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88802864e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88802864e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz.2.1655/13584:
#0: ffffffff904074b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xdd/0x1a40 fs/nfsd/nfsctl.c:1922
2 locks held by getty/14628:
#0: ffff88814da580a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e932f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.1.1904/14921:
#0: ffffffff904074b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1629
2 locks held by syz-executor/15175:
#0: ffff88803b6160e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88803b6160e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88803b6160e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88803b6160e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz-executor/15615:
#0: ffff8880830340e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880830340e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880830340e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff8880830340e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz.5.2197/16205:
#0: ffffffff904074b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xdd/0x1a40 fs/nfsd/nfsctl.c:1922
2 locks held by syz-executor/16260:
#0: ffffffff90362ca8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline]
#0: ffffffff90362ca8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3396
#1: ffffffff8e5cfdb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336
2 locks held by syz-executor/16411:
#0: ffff88806519a0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88806519a0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88806519a0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88806519a0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9ddd08 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
1 lock held by syz-executor/16912:
#0: ffffffff8e5cfdb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
watchdog+0xf70/0x12c0 kernel/hung_task.c:470
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17049 Comm: syz-executor Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:unwind_next_frame+0xb59/0x20a0 arch/x86/kernel/unwind_orc.c:583
Code: 6d 9c 30 00 e9 c0 f7 ff ff e8 23 de b6 00 e9 f4 f4 ff ff e8 e9 dd b6 00 e9 e3 f5 ff ff 4c 89 f7 e8 ac dd b6 00 e9 0f f6 ff ff <49> 8d 76 f8 ba 08 00 00 00 4d 8d 7d 34 4c 89 ef 4c 89 44 24 28 48
RSP: 0018:ffffc9000b8a76c0 EFLAGS: 00000246
RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff914e7258
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc9000b8a7778 R08: ffffffff914e725c R09: 0000000000000000
R10: 0000000000000000 R11: 00000000000133d5 R12: ffffc9000b8a7780
R13: ffffc9000b8a7730 R14: ffffc9000b8a7cf0 R15: ffffc9000b8a7cd0
FS: 0000000000000000(0000) GS:ffff888124822000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a10f539138 CR3: 0000000035838000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548
__call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3094
dentry_free+0xc2/0x160 fs/dcache.c:442
__dentry_kill+0x498/0x600 fs/dcache.c:688
shrink_kill fs/dcache.c:1114 [inline]
shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1141
shrink_dcache_parent+0xe1/0x530 fs/dcache.c:1575
do_one_tree fs/dcache.c:1604 [inline]
shrink_dcache_for_umount+0xa5/0x3e0 fs/dcache.c:1621
generic_shutdown_super+0x6c/0x390 fs/super.c:621
kill_anon_super fs/super.c:1282 [inline]
kill_litter_super+0x70/0xa0 fs/super.c:1292
deactivate_locked_super+0xc1/0x1a0 fs/super.c:474
deactivate_super fs/super.c:507 [inline]
deactivate_super+0xde/0x100 fs/super.c:503
cleanup_mnt+0x225/0x450 fs/namespace.c:1417
task_work_run+0x14d/0x240 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x86c/0x2bd0 kernel/exit.c:964
do_group_exit+0xd3/0x2a0 kernel/exit.c:1105
__do_sys_exit_group kernel/exit.c:1116 [inline]
__se_sys_exit_group kernel/exit.c:1114 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1114
x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bcab8e929
Code: Unable to access opcode bytes at 0x7f1bcab8e8ff.
RSP: 002b:00007fff36992688 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f1bcac1231f RCX: 00007f1bcab8e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007f1bcac12331 R08: 00007fff36990427 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 00000000000bad65 R15: 00007fff36992830