INFO: task hung in nfsd_nl_cache_flush_doit

Status: upstream: reported on 2026/07/16 17:02
Subsystems: nfs
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+c7eae0eb80858a2dba0f@syzkaller.appspotmail.com
First crash: 113d, last: 3h52m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
90bebe34 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in nfsd_nl_cache_flush_doit 2026/06/30 00:01 2026/06/30 00:01 2026/06/30 00:55 fff8d0a0
▶ ▼ Discussions (14)
Title Replies (including bot) Last reply
[PATCH v5 10/15] NFSD: stop registering with rpcbind after a failure in listener_set 1 (1) 2026/09/01 13:39
[PATCH v5 04/15] SUNRPC: bound the local rpcbind client timeout to 1s 1 (1) 2026/09/01 13:39
[PATCH v5 02/15] NFSD: validate transport name in listener_set before serv creation 1 (1) 2026/09/01 13:39
[PATCH v4 10/14] NFSD: stop registering with rpcbind after a failure in listener_set 1 (1) 2026/08/31 16:14
[PATCH v4 04/14] SUNRPC: bound the local rpcbind client timeout to 1s 1 (1) 2026/08/31 16:14
[PATCH v4 02/14] NFSD: validate transport name in listener_set before serv creation 1 (1) 2026/08/31 16:14
[PATCH v3 10/14] NFSD: stop registering with rpcbind after a failure in listener_set 1 (1) 2026/08/28 16:37
[PATCH v3 04/14] SUNRPC: bound the local rpcbind client timeout to 1s 1 (1) 2026/08/28 16:37
[PATCH v3 02/14] NFSD: validate transport name in listener_set before serv creation 1 (1) 2026/08/28 16:37
[PATCH v2 5/8] SUNRPC: bound the local rpcbind client timeout to 1s 1 (1) 2026/08/11 12:03
[PATCH v2 1/8] NFSD: validate transport name in listener_set before serv creation 1 (1) 2026/08/11 12:03
[PATCH 4/7] SUNRPC: bound the local rpcbind client timeout to 1s 1 (1) 2026/08/10 17:38
[PATCH 1/7] NFSD: validate transport name in listener_set before serv creation 1 (1) 2026/08/10 17:38
[syzbot] [nfs?] INFO: task hung in nfsd_nl_cache_flush_doit 4 (5) 2026/07/21 23:51

Sample crash report:
INFO: task syz.1.10744:31070 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.10744     state:D stack:27136 pid:31070 tgid:31069 ppid:5609  
task:syz.1.10744     state:D stack:27136 pid:31070 tgid:31069 ppid:5609   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 nfsd_nl_cache_flush_doit+0xb5/0x1b0 fs/nfsd/nfsctl.c:2319
 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:2579
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1923
 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: 0033:0x7fc98459e559
RSP: 002b:00007fc9853e9028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc984825fa0 RCX: 00007fc98459e559
RDX: 0000000004000880 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007fc984635ab8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc984826038 R14: 00007fc984825fa0 R15: 00007ffef3643bc8
 </TASK>

Showing all locks held in the system:
locks held by kworker/0:1/10: 3, on CPU#0:
 #0: ffff88801c06b140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88801c06b140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88801c06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88801c06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc900000f7c40 (key_gc_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc900000f7c40 (key_gc_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc900000f7c40 (key_gc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc900000f7c40 (key_gc_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffffffff8fd62ce8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #2: ffffffff8fd62ce8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:966
locks held by kworker/u8:1/13: 3, last CPU#0:
 #0: ffff888025f71940 ((wq_completion)wg-kex-wg1#13){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff888025f71940 ((wq_completion)wg-kex-wg1#13){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff888025f71940 ((wq_completion)wg-kex-wg1#13){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff888025f71940 ((wq_completion)wg-kex-wg1#13){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90000127c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90000127c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90000127c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90000127c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff88807f044a68 (&cookie->lock){++++}-{4:4}, at: wg_cookie_add_mac_to_packet+0x3e/0x1a0 drivers/net/wireguard/cookie.c:162
locks held by pr/ttyS0/32: 2, last CPU#0:
 #0: ffffffff8fc36558 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
 #0: ffffffff8fc36558 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline]
 #0: ffffffff8fc36558 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
 #1: ffffffff9bd4be78 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline]
 #1: ffffffff9bd4be78 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413
locks held by khungtaskd/33: 1, last CPU#1:
 #0: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:4/59: 4, last CPU#0:
 #0: ffff88807eec8940 ((wq_completion)wg-kex-wg2#3){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88807eec8940 ((wq_completion)wg-kex-wg2#3){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88807eec8940 ((wq_completion)wg-kex-wg2#3){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88807eec8940 ((wq_completion)wg-kex-wg2#3){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc9000200fc40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc9000200fc40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc9000200fc40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc9000200fc40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff888078d5d440 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x12e/0x810 drivers/net/wireguard/noise.c:529
 #3: ffff88807a1a3ea0 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x13f/0x810 drivers/net/wireguard/noise.c:530
locks held by getty/5366: 2, on CPU#1:
 #0: ffff88803306b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000323b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/1:4/5744: 2, last CPU#1:
 #0: ffff88801c069d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88801c069d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88801c069d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88801c069d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90004a9fc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90004a9fc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90004a9fc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90004a9fc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by kworker/0:4/25972: 6, on CPU#0:
 #0: ffff888021eb8940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff888021eb8940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff888021eb8940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff888021eb8940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc9000204fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc9000204fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc9000204fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc9000204fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff88802b53d1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #2: ffff88802b53d1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
 #3: ffff88802b5c1568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3270 [inline]
 #3: ffff88802b5c1568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5482 [inline]
 #3: ffff88802b5c1568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
 #3: ffff88802b5c1568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5889 [inline]
 #3: ffff88802b5c1568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20a1/0x4d30 drivers/usb/core/hub.c:5971
 #4: ffff88802b551360 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5483 [inline]
 #4: ffff88802b551360 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
 #4: ffff88802b551360 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5889 [inline]
 #4: ffff88802b551360 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5971
 #5: ffff8880b843bb20 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:677
locks held by syz-executor/29243: 4, last CPU#1:
 #0: ffffffff8fe365f0 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8fe365f0 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x480 kernel/fork.c:1595
 #1: ffff8880222ad900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff8880222ad900 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff888013645900 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff888013645900 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
 #3: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.5.10499/30441: 2, on CPU#0:
 #0: ffffffff912c6a08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff9009fa20 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz.1.10744/31070: 2, on CPU#1:
 #0: ffffffff912c6a08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff9009fa20 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_cache_flush_doit+0xb5/0x1b0 fs/nfsd/nfsctl.c:2319
locks held by syz-executor/31643: 2, last CPU#0:
 #0: ffff888032cb6ce0 (&xt[i].mutex){+.+.}-{4:4}, at: xt_find_table_lock+0x55/0x400 net/netfilter/x_tables.c:1336
 #1: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: __update_page_owner_free_handle+0x2e/0x4a0 mm/page_owner.c:301
locks held by syz.6.13552/5161: 2, last CPU#0:
 #0: ffff88801d2fa460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2756 [inline]
 #0: ffff88801d2fa460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #1: ffff88802bc3e910 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff88802bc3e910 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3433
locks held by syz.8.13568/5194: 2, last CPU#1:
 #0: ffff88807b4e5900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
 #0: ffff88807b4e5900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
 #1: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8fd5c920 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31643 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:222 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4923 [inline]
RIP: 0010:__lock_acquire+0x5b3/0x2de0 kernel/locking/lockdep.c:5238
Code: c7 49 63 8e a0 0b 00 00 48 83 c3 28 41 89 c4 49 39 cf 0f 8d c5 00 00 00 49 83 ff 31 0f 83 84 00 00 00 48 8b 03 25 ff 1f 00 00 <48> 0f a3 05 15 54 f8 13 73 10 48 69 c0 c8 00 00 00 48 8d 88 d0 c4
RSP: 0018:ffffc90004f3f068 EFLAGS: 00000002
RAX: 00000000000005ec RBX: ffff8880310a2b60 RCX: 0000000000000007
RDX: 0000000000000004 RSI: 0000000000000005 RDI: 2e00000000000000
RBP: ffff8880310a2c08 R08: ffffffff8244e50a R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100afc32a5 R12: 0000000000000004
R13: 0000000000000000 R14: ffff8880310a1f40 R15: 0000000000000002
FS:  000055557739f500(0000) GS:ffff888123abf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4512d556c8 CR3: 000000004a97e000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock_sched include/linux/rcupdate.h:947 [inline]
 pfn_valid+0xd6/0x490 include/linux/mmzone.h:2276
 page_table_check_set+0x25/0x530 mm/page_table_check.c:105
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:447 [inline]
 __copy_present_ptes mm/memory.c:1200 [inline]
 copy_present_ptes mm/memory.c:1279 [inline]
 copy_pte_range mm/memory.c:1402 [inline]
 copy_pmd_range+0x4adc/0x5c10 mm/memory.c:1490
 copy_pud_range mm/memory.c:1527 [inline]
 copy_p4d_range mm/memory.c:1551 [inline]
 copy_page_range+0xc82/0x1290 mm/memory.c:1637
 dup_mmap+0xf17/0x1dc0 mm/mmap.c:1819
 dup_mm kernel/fork.c:1543 [inline]
 copy_mm+0x115/0x480 kernel/fork.c:1595
 copy_process+0x1ea3/0x4480 kernel/fork.c:2321
 kernel_clone+0x2d7/0x940 kernel/fork.c:2781
 __do_sys_clone kernel/fork.c:2923 [inline]
 __se_sys_clone kernel/fork.c:2907 [inline]
 __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2907
 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: 0033:0x7f4511fc6fd2
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffebec985a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffebec985a0 RCX: 00007f4511fc6fd2
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffebec9872c R08: 0000000000000000 R09: 0000000000000001
R10: 000055557739f7d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000000f8f96 R15: 00007ffebec98780
 </TASK>

Crashes (437):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/18 21:36 upstream a0ff06b3a7bd 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 16:31 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/11 15:46 upstream a5ebb76233b7 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/09/27 23:20 upstream 104484baf748 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/09/21 07:00 upstream 93f51579e7df 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/07/12 12:21 upstream 44696aa3a489 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/07/09 17:33 upstream 0e35b9b6ec0f b9f1ceaa .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/06/28 07:46 upstream 780d569e6c4b fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/20 02:20 net 78731b46967e 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/19 14:47 net 07bd391eb957 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/19 12:57 net 07bd391eb957 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/19 11:13 net 07bd391eb957 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/19 01:23 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 22:59 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 18:25 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 08:37 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 07:16 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 04:56 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/18 01:04 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/17 23:55 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/17 19:51 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/17 18:32 net 7ec48f396a1d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/17 08:20 net 00accbd9d502 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/16 18:35 net 191aa41548b2 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/16 16:06 net 191aa41548b2 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/16 12:20 net 191aa41548b2 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/16 08:06 net 191aa41548b2 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/16 00:35 net f88bb3606e4b 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/15 21:45 net f88bb3606e4b 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/15 05:52 net 513444cc62e2 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/14 21:30 net 513444cc62e2 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/14 18:32 net 513444cc62e2 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/14 14:40 net 513444cc62e2 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/14 02:07 net 8e2fbe0e75d3 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/13 23:37 net 8e2fbe0e75d3 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/13 20:20 net 8e2fbe0e75d3 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/13 17:21 net 8e2fbe0e75d3 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/13 15:49 net 8e2fbe0e75d3 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/13 07:39 net 8e2fbe0e75d3 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/12 12:33 net af32da41b032 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/11 20:53 net af32da41b032 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/11 19:28 net af32da41b032 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/11 12:43 net af32da41b032 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/10 02:41 net af32da41b032 a8add9cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/10 00:58 net af32da41b032 a8add9cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/09 22:49 net af32da41b032 a8add9cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/09 21:23 net af32da41b032 a8add9cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/09 16:46 net af32da41b032 a8add9cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/06 22:29 net d5a007b9b457 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/06 12:13 net d5a007b9b457 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/05 20:19 net aaaaf87ea99b 1995e6c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/05 11:01 net 5158353121ba 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/15 17:17 net-next 73022f605c44 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/06 23:53 net-next a5e7d8e446af f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/06 13:43 net-next c0402d7640a8 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/06 11:45 net-next c0402d7640a8 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/05 14:12 net-next 8b4e7209c842 1995e6c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/04 23:15 net-next cfb7793d1bc0 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/04 20:30 net-next cfb7793d1bc0 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/10/04 14:10 net-next cfb7793d1bc0 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
2026/09/25 11:36 linux-next 4c253ac4b29b f281d9d2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in nfsd_nl_cache_flush_doit
2026/08/07 23:39 linux-next cc2b5f627e8c e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in nfsd_nl_cache_flush_doit
* Struck through repros no longer work on HEAD.