Subject: [syzbot] [net?] INFO: task hung in nsim_create (2)

From: syzbot <[email-masked]>
Date: Wed, 24 Jul 2024 11:05:21 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    68b59730459e Merge tag 'perf-tools-for-v6.11-2024-07-16' o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13e0a195980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b6230d83d52af231
dashboard link: https://syzkaller.appspot.com/bug?extid=90fd70a665715bd10258
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2ed0d621f118/disk-68b59730.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/36b453c7acac/vmlinux-68b59730.xz
kernel image: https://storage.googleapis.com/syzbot-assets/069a896ef41a/bzImage-68b59730.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

INFO: task kworker/u8:5:570 blocked for more than 143 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5    state:D stack:20528 pid:570   tgid:570   ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:678 [inline]
 nsim_create+0x408/0x890 drivers/net/netdevsim/netdev.c:750
 __nsim_dev_port_add+0x6c0/0xae0 drivers/net/netdevsim/dev.c:1390
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1446 [inline]
 nsim_dev_reload_create drivers/net/netdevsim/dev.c:1498 [inline]
 nsim_dev_reload_up+0x69b/0x8e0 drivers/net/netdevsim/dev.c:985
 devlink_reload+0x478/0x870 net/devlink/dev.c:474
 devlink_pernet_pre_exit+0x1f3/0x440 net/devlink/core.c:509
 ops_pre_exit_list net/core/net_namespace.c:163 [inline]
 cleanup_net+0x615/0xcc0 net/core/net_namespace.c:620
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task kworker/u8:7:2410 blocked for more than 144 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7    state:D stack:23312 pid:2410  tgid:2410  ppid:2      flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4194
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task dhcpcd:4769 blocked for more than 145 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D
 stack:20384 pid:4769  tgid:4769  ppid:4768   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6644
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
 ___sys_sendmsg net/socket.c:2651 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9d6db7da4b
RSP: 002b:00007ffd2f22e8c8 EFLAGS: 00000246
 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9d6daa56c0 RCX: 00007f9d6db7da4b
RDX: 0000000000000000 RSI: 00007ffd2f242a78 RDI: 0000000000000005
RBP: 0000000000000005 R08: 0000000000000000 R09: 00007ffd2f242a78
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 00007ffd2f242a78 R14: 0000000000000030 R15: 0000000000000001
 </TASK>
INFO: task udevd:5105 blocked for more than 146 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D
 stack:24864 pid:5105  tgid:5105  ppid:4555   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 device_lock include/linux/device.h:1009 [inline]
 uevent_show+0x17d/0x340 drivers/base/core.c:2743
 dev_attr_show+0x55/0xc0 drivers/base/core.c:2437
 sysfs_kf_seq_show+0x331/0x4c0 fs/sysfs/file.c:59
 seq_read_iter+0x445/0xd60 fs/seq_file.c:230
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x9bd/0xbc0 fs/read_write.c:476
 ksys_read+0x1a0/0x2c0 fs/read_write.c:619
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda18b16b6a
RSP: 002b:00007ffcf336bed8 EFLAGS: 00000246
 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00005588202d8730 RCX: 00007fda18b16b6a
RDX: 0000000000001000 RSI: 0000558820307980 RDI: 0000000000000008
RBP: 00005588202d8730 R08: 0000000000000008 R09: 0000000000000008
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007ffcf336c3b8 R15: 000000000000000a
 </TASK>
INFO: task syz-executor:5304 blocked for more than 147 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:20216 pid:5304  tgid:5304  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 nsim_destroy+0x71/0x5c0 drivers/net/netdevsim/netdev.c:773
 __nsim_dev_port_del+0x14b/0x1b0 drivers/net/netdevsim/dev.c:1425
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1437 [inline]
 nsim_dev_reload_destroy+0x28a/0x490 drivers/net/netdevsim/dev.c:1658
 nsim_drv_remove+0x58/0x160 drivers/net/netdevsim/dev.c:1673
 device_remove drivers/base/dd.c:566 [inline]
 __device_release_driver drivers/base/dd.c:1270 [inline]
 device_release_driver_internal+0x4a9/0x7c0 drivers/base/dd.c:1293
 bus_remove_device+0x34f/0x420 drivers/base/bus.c:574
 device_del+0x57a/0x9b0 drivers/base/core.c:3868
 device_unregister+0x20/0xc0 drivers/base/core.c:3909
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:462 [inline]
 del_device_store+0x363/0x480 drivers/net/netdevsim/bus.c:226
 kernfs_fop_write_iter+0x3a1/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9e2b3746df
RSP: 002b:00007f9e2b62f220 EFLAGS: 00000293
 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f9e2b3746df
RDX: 0000000000000001 RSI: 00007f9e2b62f270 RDI: 0000000000000005
RBP: 00007f9e2b3e45b2 R08: 0000000000000000 R09: 00007f9e2b62f077
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007f9e2b62f270 R14: 00007f9e2c034620 R15: 0000000000000003
 </TASK>
INFO: task syz-executor:5325 blocked for more than 148 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:21104 pid:5325  tgid:5325  ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6644
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 __sys_sendto+0x3a4/0x4f0 net/socket.c:2204
 __do_sys_sendto net/socket.c:2216 [inline]
 __se_sys_sendto net/socket.c:2212 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2212
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1d9e3778ec
RSP: 002b:00007f1d9e62f630 EFLAGS: 00000293
 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f1d9f034620 RCX: 00007f1d9e3778ec
RDX: 0000000000000020 RSI: 00007f1d9f034670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f1d9e62f684 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f1d9f034670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:5383 blocked for more than 149 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:21728 pid:5383  tgid:5383  ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6644
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 __sys_sendto+0x3a4/0x4f0 net/socket.c:2204
 __do_sys_sendto net/socket.c:2216 [inline]
 __se_sys_sendto net/socket.c:2212 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2212
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4baeb778ec
RSP: 002b:00007f4baee2f6b0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f4baf834620 RCX: 00007f4baeb778ec
RDX: 000000000000003c RSI: 00007f4baf834670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f4baee2f704 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f4baf834670 R15: 0000000000000000
 </TASK>
INFO: task syz.3.62:5420 blocked for more than 150 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.62        state:D stack:22288 pid:5420  tgid:5419  ppid:5118   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 netdev_wait_allrefs_any net/core/dev.c:10622 [inline]
 netdev_run_todo+0x7b2/0x1000 net/core/dev.c:10741
 rtnl_unlock net/core/rtnetlink.c:152 [inline]
 rtnetlink_rcv_msg+0x748/0xcf0 net/core/rtnetlink.c:6648
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
 ___sys_sendmsg net/socket.c:2651 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b41f75b59
RSP: 002b:00007f5b42cf2048 EFLAGS: 00000246
 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5b42105f60 RCX: 00007f5b41f75b59
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000006
RBP: 00007f5b41fe4e5d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f5b42105f60 R15: 00007f5b4222fa78
 </TASK>
INFO: task syz-executor:5430 blocked for more than 151 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:25264 pid:5430  tgid:5430  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 register_nexthop_notifier+0x84/0x290 net/ipv4/nexthop.c:3871
 ops_init+0x359/0x610 net/core/net_namespace.c:139
 setup_net+0x515/0xca0 net/core/net_namespace.c:343
 copy_net_ns+0x4e2/0x7b0 net/core/net_namespace.c:508
 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x619/0xc10 kernel/fork.c:3308
 __do_sys_unshare kernel/fork.c:3379 [inline]
 __se_sys_unshare kernel/fork.c:3377 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3377
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f61f45772b7
RSP: 002b:00007f61f482ffa8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f61f45e4bd1 RCX: 00007f61f45772b7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 0000000000000000 R08: 00007f61f5237d60 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000000c
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000009
 </TASK>
INFO: task syz-executor:5432 blocked for more than 152 seconds.
      Not tainted 6.10.0-syzkaller-08280-g68b59730459e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:25712 pid:5432  tgid:5432  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 register_nexthop_notifier+0x84/0x290 net/ipv4/nexthop.c:3871
 ops_init+0x359/0x610 net/core/net_namespace.c:139
 setup_net+0x515/0xca0 net/core/net_namespace.c:343
 copy_net_ns+0x4e2/0x7b0 net/core/net_namespace.c:508
 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x619/0xc10 kernel/fork.c:3308

---
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup