INFO: task hung in devlink_pernet_pre_exit (3)

Status: upstream: reported on 2026/09/24 21:23
Reported-by: syzbot+9d90661a2f1f7667c6dc@syzkaller.appspotmail.com
First crash: 6d09h, last: 6d09h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in devlink_pernet_pre_exit net 1 1 1806d 1806d 0/29 auto-closed as invalid on 2022/01/18 07:25
linux-5.15 INFO: task hung in devlink_pernet_pre_exit (2) 1 1 477d 477d 0/3 auto-obsoleted due to no activity on 2025/09/18 20:38
upstream INFO: task hung in devlink_pernet_pre_exit (2) net 1 32 692d 710d 28/29 fixed on 2024/11/12 23:31
upstream INFO: task hung in devlink_pernet_pre_exit (3) prio:low net 1 34 9d01h 62d 0/29 upstream: reported on 2026/07/31 00:11
linux-5.15 INFO: task hung in devlink_pernet_pre_exit 1 1 748d 748d 0/3 auto-obsoleted due to no activity on 2024/12/21 18:04

Sample crash report:
INFO: task syz-executor:5459 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:24320 pid: 5459 ppid:     1 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 devlink_pernet_pre_exit+0xa4/0x310 net/core/devlink.c:11534
 ops_pre_exit_list net/core/net_namespace.c:162 [inline]
 setup_net+0x631/0xa10 net/core/net_namespace.c:350
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226
 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3178
 __do_sys_unshare kernel/fork.c:3255 [inline]
 __se_sys_unshare kernel/fork.c:3253 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3253
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd29998a427
RSP: 002b:00007ffd83ac4b98 EFLAGS: 00000202 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fd299c10f40 RCX: 00007fd29998a427
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007fd299c117b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffd83ac4dd8 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:5463 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:24320 pid: 5463 ppid:     1 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 devlink_pernet_pre_exit+0xa4/0x310 net/core/devlink.c:11534
 ops_pre_exit_list net/core/net_namespace.c:162 [inline]
 setup_net+0x631/0xa10 net/core/net_namespace.c:350
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226
 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3178
 __do_sys_unshare kernel/fork.c:3255 [inline]
 __se_sys_unshare kernel/fork.c:3253 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3253
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc3552a9427
RSP: 002b:00007ffc18be24c8 EFLAGS: 00000202
 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fc35552ff40 RCX: 00007fc3552a9427
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007fc3555307b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffc18be2708 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:5469 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:24320 pid: 5469 ppid:     1 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 devlink_pernet_pre_exit+0xa4/0x310 net/core/devlink.c:11534
 ops_pre_exit_list net/core/net_namespace.c:162 [inline]
 setup_net+0x631/0xa10 net/core/net_namespace.c:350
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226
 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3178
 __do_sys_unshare kernel/fork.c:3255 [inline]
 __se_sys_unshare kernel/fork.c:3253 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3253
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4bd69c5427
RSP: 002b:00007ffffc42d298 EFLAGS: 00000202
 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f4bd6c4bf40 RCX: 00007f4bd69c5427
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007f4bd6c4c7b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffffc42d4d8 R15: 0000000000000000
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5496 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:io_serial_in+0x73/0xb0 drivers/tty/serial/8250/8250_port.c:461
Code: e8 22 4d 24 fd 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 c3 80 69 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 44 89 f9 80 e1 07 38 c1 7c aa 4c
RSP: 0018:ffffc90002e0ed98 EFLAGS: 00000002
RAX: 1ffffffff2cc3d00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000020 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520005c1da8 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff9661e8a0 R15: 0000000000000000
FS:  0000555591a33500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f24d274f82c CR3: 0000000078c2d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:116 [inline]
 wait_for_xmitr+0xc7/0x240 drivers/tty/serial/8250/8250_port.c:2069
 serial8250_console_putchar+0x1a/0x50 drivers/tty/serial/8250/8250_port.c:3315
 uart_console_write+0xaa/0x100 drivers/tty/serial/serial_core.c:1981
 serial8250_console_write+0xb90/0xf50 drivers/tty/serial/8250/8250_port.c:3392
 call_console_drivers kernel/printk/printk.c:-1 [inline]
 console_unlock+0xb47/0x10f0 kernel/printk/printk.c:2744
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 __dynamic_pr_debug+0x196/0x240 lib/dynamic_debug.c:619
 ensure_safe_net_sysctl net/sysctl_net.c:134 [inline]
 register_net_sysctl+0x299/0x350 net/sysctl_net.c:167
 __devinet_sysctl_register+0x2ba/0x380 net/ipv4/devinet.c:2603
 devinet_sysctl_register+0x17c/0x1f0 net/ipv4/devinet.c:2643
 inetdev_init+0x28c/0x4d0 net/ipv4/devinet.c:277
 inetdev_event+0x26f/0x1350 net/ipv4/devinet.c:1543
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 register_netdevice+0x12a8/0x1720 net/core/dev.c:10454
 __ip_tunnel_create+0x2c7/0x390 net/ipv4/ip_tunnel.c:267
 ip_tunnel_init_net+0x246/0x710 net/ipv4/ip_tunnel.c:1084
 vti_init_net+0x2b/0xf0 net/ipv4/ip_vti.c:504
 ops_init+0x360/0x5f0 net/core/net_namespace.c:138
 setup_net+0x39e/0xa10 net/core/net_namespace.c:333
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226
 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3178
 __do_sys_unshare kernel/fork.c:3255 [inline]
 __se_sys_unshare kernel/fork.c:3253 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3253
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8fc62bd427
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd16fc8ae8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f8fc6543f40 RCX: 00007f8fc62bd427
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007f8fc65447b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffd16fc8d28 R15: 0000000000000000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/24 21:22 linux-5.15.y 0248c33e835e 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in devlink_pernet_pre_exit
* Struck through repros no longer work on HEAD.