INFO: task hung in ip_tunnel_init_net

Status: upstream: reported on 2026/09/08 16:48
Reported-by: syzbot+666b424bdc01e7afd243@syzkaller.appspotmail.com
First crash: 9d01h, last: 9d01h
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in ip_tunnel_init_net (2) 1 1 651d 651d 0/3 auto-obsoleted due to no activity on 2025/03/15 13:31
linux-5.15 INFO: task hung in ip_tunnel_init_net 1 1 671d 671d 0/3 auto-obsoleted due to no activity on 2025/02/23 13:12
upstream INFO: task hung in ip_tunnel_init_net (3) netfilter 1 41 674d 706d 28/29 fixed on 2024/11/12 23:31
linux-6.1 INFO: task hung in ip_tunnel_init_net 1 2 799d 834d 0/3 auto-obsoleted due to no activity on 2024/10/18 03:42
linux-4.19 INFO: task hung in ip_tunnel_init_net 1 18 1701d 1740d 0/1 auto-closed as invalid on 2022/05/20 09:22
upstream INFO: task hung in ip_tunnel_init_net net 1 2 2140d 2202d 0/29 auto-closed as invalid on 2021/02/05 10:58
linux-4.19 INFO: task hung in ip_tunnel_init_net (2) 1 1 1320d 1320d 0/1 upstream: reported on 2023/02/05 00:06
upstream INFO: task hung in ip_tunnel_init_net (4) net 1 9 534d 666d 0/29 auto-obsoleted due to no activity on 2025/06/30 02:27
upstream INFO: task hung in ip_tunnel_init_net (2) net 1 3 1246d 1370d 0/29 auto-obsoleted due to no activity on 2023/07/18 20:51
upstream INFO: task can't die in ip_tunnel_init_net net 1 11 1794d 1795d 0/29 auto-closed as invalid on 2022/02/16 13:24

Sample crash report:
INFO: task syz-executor:26922 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:25000 pid:26922 ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 ip_tunnel_init_net+0x2d2/0x7c0 net/ipv4/ip_tunnel.c:1103
 ops_init+0x391/0x640 net/core/net_namespace.c:139
 setup_net+0x3b6/0xa20 net/core/net_namespace.c:343
 copy_net_ns+0x35e/0x5d0 net/core/net_namespace.c:520
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:228
 ksys_unshare+0x4fa/0x8f0 kernel/fork.c:3444
 __do_sys_unshare kernel/fork.c:3518 [inline]
 __se_sys_unshare kernel/fork.c:3516 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3516
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4fca39f427
RSP: 002b:00007ffc1dee3c38 EFLAGS: 00000202 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f4fca625f40 RCX: 00007f4fca39f427
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007f4fca6267b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffc1dee3e78 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:26985 blocked for more than 150 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:25384 pid:26985 ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 rtnl_lock net/core/rtnetlink.c:78 [inline]
 rtnetlink_rcv_msg+0x7ed/0xf90 net/core/rtnetlink.c:6481
 netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x4a9/0x6b0 net/socket.c:2201

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/08 16:48 linux-6.6.y 8b73de7da85f 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in ip_tunnel_init_net
* Struck through repros no longer work on HEAD.