syzbot


INFO: task hung in nfsd_nl_threads_get_doit

Status: upstream: reported on 2024/06/24 13:18
Subsystems: nfs
[Documentation on labels]
Reported-by: syzbot+c0831b61d6ade1e2d098@syzkaller.appspotmail.com
First crash: 645d, last: 3h59m
Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly nfs report (Jul 2025) 0 (1) 2025/07/04 12:38
[syzbot] Monthly nfs report (Jun 2025) 0 (1) 2025/06/03 09:38
[syzbot] [nfs?] INFO: task hung in nfsd_nl_threads_get_doit 0 (1) 2024/06/24 13:18

Sample crash report:
INFO: task syz.4.11586:3999 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.4.11586     state:D stack:27048 pid:3999  tgid:3998  ppid:5805   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286
 rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1647
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
 rt_mutex_slowlock+0x2dc/0x7b0 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:552
 nfsd_nl_threads_get_doit+0x1c0/0x790 fs/nfsd/nfsctl.c:1683
 genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x831/0x9f0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa4e/0xac0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x1c3/0x2a0 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe02437c799
RSP: 002b:00007fe0225d6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe0245f5fa0 RCX: 00007fe02437c799
RDX: 0000000000000000 RSI: 00002000000032c0 RDI: 0000000000000003
RBP: 00007fe024412bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0245f6038 R14: 00007fe0245f5fa0 R15: 00007ffed4f92c98
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5558:
 #0: ffff8880370350a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:27/2372:
2 locks held by syz.7.11340/3317:
 #0: ffffffff8f1c8820 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8e0e7078 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x13e/0x1690 fs/nfsd/nfsctl.c:1893
2 locks held by syz.4.11586/3999:
 #0: ffffffff8f1c8820 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8e0e7078 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790 fs/nfsd/nfsctl.c:1683

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 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: 2372 Comm: kworker/u8:27 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: bat_events batadv_dat_purge
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline]
RIP: 0010:check_preemption_disabled+0x2a/0xe0 lib/smp_processor_id.c:19
Code: 55 41 57 41 56 53 65 8b 05 47 f3 2b 07 65 8b 0d 3c f3 2b 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d e9 99 a5 03 00 cc 9c 59 <f7> c1 00 02 00 00 74 ea 65 4c 8b 3d ee f2 2b 07 41 f6 47 2f 04 74
RSP: 0018:ffffc9000674fa28 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8b4b2a80 RDI: ffffffff8ba64880
RBP: 1ffff110051e7544 R08: ffffffff8f6a32b7 R09: 1ffffffff1ed4656
R10: dffffc0000000000 R11: fffffbfff1ed4657 R12: 0000000000000286
R13: dffffc0000000000 R14: ffff888028f3aa24 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888126340000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b5b58b9a38 CR3: 000000000dbba000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __local_bh_enable_ip+0xe3/0x2b0 kernel/softirq.c:283
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 spin_unlock_bh include/linux/spinlock_rt.h:116 [inline]
 __batadv_dat_purge+0x344/0x400 net/batman-adv/distributed-arp-table.c:185
 batadv_dat_purge+0x20/0x70 net/batman-adv/distributed-arp-table.c:204
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (1229):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/02 01:57 upstream 11439c4635ed 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in nfsd_nl_threads_get_doit
2026/02/26 01:24 upstream d9d32e5bd5a4 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 05:41 upstream 8bf22c33e7a1 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nfsd_nl_threads_get_doit
2026/02/15 20:05 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in nfsd_nl_threads_get_doit
2026/02/07 07:54 upstream 2687c848e578 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in nfsd_nl_threads_get_doit
2026/02/02 17:20 upstream 18f7fcd5e69a 018ebef2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in nfsd_nl_threads_get_doit
2026/01/30 19:57 upstream 4d310797262f ea6dba22 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in nfsd_nl_threads_get_doit
2025/12/11 09:07 upstream d358e5254674 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in nfsd_nl_threads_get_doit
2024/06/12 22:52 upstream cea2a26553ac 2aa5052f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in nfsd_nl_threads_get_doit
2026/03/01 19:17 net 9439a661c2e8 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/03/01 14:01 net 9439a661c2e8 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/25 06:16 net 1348659dc92e 787dfb7c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 23:18 net d4f687fbbce4 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 15:15 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 13:27 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 11:56 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 10:09 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 08:30 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 07:21 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 04:47 net 3f1af4853076 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/21 02:47 net 3f1af4853076 741f5161 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 21:26 net bfd264fbbbca 741f5161 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 20:00 net bfd264fbbbca 741f5161 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 19:11 net bfd264fbbbca 741f5161 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 14:40 net bfd264fbbbca 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 13:30 net bfd264fbbbca 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 12:11 net bfd264fbbbca 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/16 16:56 net ee5492fd88cf 5d52cba5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/15 14:31 net ee5492fd88cf 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/13 21:59 net 8383522821c6 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/11 02:31 net 3a23b80dd72d 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/06 08:49 net c89477ad7944 f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/06 07:26 net c89477ad7944 f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/06 04:34 net c89477ad7944 f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/05 20:43 net 7d6ba706ae5e 4936e85c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/05 16:48 net 7d6ba706ae5e 4936e85c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/05 11:34 net 7d6ba706ae5e 4936e85c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/03 06:12 net 1c172febdf06 d78927dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/01 04:34 net fdf3f6800be3 35764559 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/01 02:53 net fdf3f6800be3 35764559 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/01 01:21 net fdf3f6800be3 35764559 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2024/06/23 00:43 net 49bbeb5719c2 edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2024/06/21 01:32 net d5a7fc58da03 dac2aa43 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/03/02 11:05 net-next 01857fc712f6 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/03/02 06:47 net-next 01857fc712f6 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/03/02 03:12 net-next 01857fc712f6 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/03/02 00:47 net-next 01857fc712f6 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/03/01 01:37 net-next ded4a02e7d04 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/18 19:08 net-next 37a93dd5c49b 77d4d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/18 10:52 net-next 37a93dd5c49b 39751c21 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/09 06:41 net-next 57be33f85e36 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/08 18:55 net-next 57be33f85e36 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/07 22:51 net-next 57be33f85e36 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/06 10:19 net-next a182a62ff77f f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/03 17:20 net-next fae1c659d7bd 6df4c87a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/26 14:26 linux-next 877552aa8758 ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in nfsd_nl_threads_get_doit
2026/02/20 17:41 linux-next d4906ae14a5f 741f5161 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
2026/02/15 11:25 linux-next 635c467cc14e 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in nfsd_nl_threads_get_doit
* Struck through repros no longer work on HEAD.