INFO: task hung in gtp_net_exit (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=123008ca880000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=798bff8868e742784890
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+798bff...@syzkaller.appspotmail.com

Bluetooth: hci4: command 0x0419 tx timeout
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
Bluetooth: hci1: command 0x0406 tx timeout
Bluetooth: hci2: command 0x0406 tx timeout
INFO: task syz-executor.3:2776 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3 D26424 2776 1 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619
__mutex_lock_common kernel/locking/mutex.c:1016 [inline]
__mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078
gtp_net_exit+0x1ba/0x380 drivers/net/gtp.c:1360
ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153
setup_net+0x3d1/0x720 net/core/net_namespace.c:333
copy_net_ns+0x1f7/0x340 net/core/net_namespace.c:439
create_new_namespaces+0x3f6/0x7b0 kernel/nsproxy.c:107
unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:206
ksys_unshare+0x36c/0x9a0 kernel/fork.c:2542
__do_sys_unshare kernel/fork.c:2610 [inline]
__se_sys_unshare kernel/fork.c:2608 [inline]
__x64_sys_unshare+0x2d/0x40 kernel/fork.c:2608
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f33231a8b67
Code: Bad RIP value.
RSP: 002b:00007fffc1ce7998 EFLAGS: 00000202 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fffc1ce7fd8 RCX: 00007f33231a8b67
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000006
R13: 00007fffc1ce7a70 R14: 00007f33232c84f8 R15: 0000000000000006

Showing all locks held in the system:
5 locks held by systemd/1:
2 locks held by kworker/0:1/14:
1 lock held by khungtaskd/1570:
#0: 0000000075c8e1e5 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
4 locks held by kworker/u4:4/2927:
#0: 00000000a0172508 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 000000006c6faa8c (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 00000000dbcc7798 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521
#3: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: netdev_run_todo+0x719/0xab0 net/core/dev.c:9005
3 locks held by kworker/0:2/4384:
#0: 0000000041a9ece9 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 00000000cda235e9 ((addr_chk_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4476
1 lock held by systemd-journal/4692:
1 lock held by systemd-timesyn/6155:
1 lock held by syz-fuzzer/8096:
3 locks held by kworker/u4:8/11105:
3 locks held by kworker/0:0/23312:
#0: 000000000996ef96 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 00000000481081a2 ((linkwatch_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:236
1 lock held by syz-executor.1/28883:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: netdev_run_todo+0x719/0xab0 net/core/dev.c:9005
2 locks held by agetty/31742:
#0: 0000000013ddd9a7 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 0000000049e86f3a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
2 locks held by syz-executor.5/2630:
1 lock held by syz-executor.0/2701:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: netdev_run_todo+0x719/0xab0 net/core/dev.c:9005
1 lock held by syz-executor.3/2771:
2 locks held by syz-executor.3/2776:
#0: 00000000dbcc7798 (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1d8/0x340 net/core/net_namespace.c:435
#1: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: gtp_net_exit+0x1ba/0x380 drivers/net/gtp.c:1360
2 locks held by syz-executor.2/2786:
#0: 00000000dbcc7798 (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1d8/0x340 net/core/net_namespace.c:435
#1: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: gtp_net_exit+0x1ba/0x380 drivers/net/gtp.c:1360
2 locks held by syz-executor.0/2797:
#0: 00000000dbcc7798 (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1d8/0x340 net/core/net_namespace.c:435
#1: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: gtp_net_exit+0x1ba/0x380 drivers/net/gtp.c:1360
1 lock held by syz-executor.3/2862:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.2/2873:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.0/2890:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.3/2895:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.2/2915:
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 00000000ae4c8ac3 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779

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

NMI backtrace for cpu 1
CPU: 1 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
watchdog+0x991/0xe60 kernel/hung_task.c:287
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2771 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
RIP: 0010:unwind_next_frame+0xf7e/0x1400 arch/x86/kernel/unwind_orc.c:555
Code: b3 02 00 00 83 e0 07 40 38 c6 41 0f 9e c0 40 84 f6 0f 95 c0 41 84 c0 0f 85 9a 02 00 00 49 0f bf 77 02 4c 89 f7 48 03 74 24 68 <e8> ad ee ff ff 84 c0 0f 85 a0 fe ff ff e9 e6 f4 ff ff 49 8d 56 40
RSP: 0018:ffff8880ba0078b0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff11017400f1f RCX: ffffffff8b91230f
RDX: ffff8880ba007a20 RSI: ffff88809e2474e0 RDI: ffff8880ba0079e0
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: ffff8880ba007a3f R11: 0000000000074071 R12: ffff88809e2474f8
R13: ffff8880ba007a15 R14: ffff8880ba0079e0 R15: ffffffff8b91230a
FS: 00007f3706174700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b4caa5b2f8 CR3: 00000000a3c57000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__save_stack_trace+0x9f/0x190 arch/x86/kernel/stacktrace.c:44
save_stack mm/kasan/kasan.c:448 [inline]
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:553
kmem_cache_alloc_node_trace+0x151/0x3b0 mm/slab.c:3668
__do_kmalloc_node mm/slab.c:3688 [inline]
__kmalloc_node_track_caller+0x38/0x70 mm/slab.c:3703
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0xae/0x560 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:995 [inline]
bcm_can_tx+0x259/0x800 net/can/bcm.c:287
bcm_tx_timeout_tsklet+0x1f0/0x3a0 net/can/bcm.c:414
tasklet_action_common.constprop.0+0x265/0x360 kernel/softirq.c:522
__do_softirq+0x265/0x980 kernel/softirq.c:292
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1092
</IRQ>
do_softirq.part.0+0x160/0x1c0 kernel/softirq.c:336
do_softirq kernel/softirq.c:328 [inline]
__local_bh_enable_ip+0x20e/0x270 kernel/softirq.c:189
local_bh_enable include/linux/bottom_half.h:32 [inline]
get_next_corpse net/netfilter/nf_conntrack_core.c:1907 [inline]
nf_ct_iterate_cleanup+0x239/0x520 net/netfilter/nf_conntrack_core.c:1930
nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2015 [inline]
nf_ct_iterate_cleanup_net+0x113/0x170 net/netfilter/nf_conntrack_core.c:2000
masq_device_event+0xae/0xe0 net/ipv6/netfilter/nf_nat_masquerade_ipv6.c:77
notifier_call_chain+0xc0/0x230 kernel/notifier.c:93
call_netdevice_notifiers net/core/dev.c:1762 [inline]
dev_close_many+0x323/0x670 net/core/dev.c:1514
rollback_registered_many+0x2f7/0xe70 net/core/dev.c:8173
rollback_registered+0xe9/0x1b0 net/core/dev.c:8238
unregister_netdevice_queue+0x1de/0x3e0 net/core/dev.c:9305
unregister_netdevice include/linux/netdevice.h:2615 [inline]
__tun_detach+0x100d/0x1320 drivers/net/tun.c:745
tun_detach drivers/net/tun.c:762 [inline]
tun_chr_close+0xd9/0x180 drivers/net/tun.c:3323
__fput+0x2ce/0x890 fs/file_table.c:278
task_work_run+0x148/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0xbf3/0x2be0 kernel/exit.c:870
do_group_exit+0x125/0x310 kernel/exit.c:967
get_signal+0x3f2/0x1f70 kernel/signal.c:2589
do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799
exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f3707c225a9
Code: Bad RIP value.
RSP: 002b:00007f3706174168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 0000000000000044 RBX: 00007f3707d43050 RCX: 00007f3707c225a9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000004
RBP: 00007f3707c7d7b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd0d49dd0f R14: 00007f3706174300 R15: 0000000000022000


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.