INFO: task hung in disconnect_work (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=1730b154880000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=4c809de735cf761a4b88
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4c809d...@syzkaller.appspotmail.com

Bluetooth: hci13: command 0x040f tx timeout
Bluetooth: hci14: command 0x040f tx timeout
Bluetooth: hci12: command 0x0419 tx timeout
Bluetooth: hci13: command 0x0419 tx timeout
Bluetooth: hci14: command 0x0419 tx timeout
INFO: task kworker/1:2:3497 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.
kworker/1:2 D26504 3497 2 0x80000000
Workqueue: events disconnect_work
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
disconnect_work+0x18/0x200 net/wireless/sme.c:664
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
INFO: task syz-executor.4:29890 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.4 D28752 29890 8132 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
genl_lock net/netlink/genetlink.c:33 [inline]
genl_rcv_msg+0x12f/0x160 net/netlink/genetlink.c:625
netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
genl_rcv+0x24/0x40 net/netlink/genetlink.c:638
netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:661
___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
__sys_sendmsg net/socket.c:2265 [inline]
__do_sys_sendmsg net/socket.c:2274 [inline]
__se_sys_sendmsg net/socket.c:2272 [inline]
__x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7ff684777669
Code: Bad RIP value.
RSP: 002b:00007ff6830ca168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff684899050 RCX: 00007ff684777669
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00007ff6847d2560 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe9a6ff81f R14: 00007ff6830ca300 R15: 0000000000022000
INFO: task syz-executor.1:29864 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.1 D28648 29864 8133 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
ip_mc_drop_socket+0x89/0x260 net/ipv4/igmp.c:2702
inet_release+0x49/0x1e0 net/ipv4/af_inet.c:414
__sock_release+0xcd/0x2a0 net/socket.c:599
sock_close+0x15/0x20 net/socket.c:1214
__fput+0x2ce/0x890 fs/file_table.c:278
task_work_run+0x148/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
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: 0033:0x7fd9c6e1543b
Code: Bad RIP value.
RSP: 002b:00007ffcda62f680 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000009 RCX: 00007fd9c6e1543b
RDX: 0000001b2f920000 RSI: 0000001b2f924200 RDI: 0000000000000008
RBP: 00007fd9c6f86980 R08: 0000000000000000 R09: 000000003253460c
R10: 001735a723529653 R11: 0000000000000293 R12: 00000000000790a1
R13: 00007ffcda62f780 R14: 00007fd9c6f85120 R15: 0000000000000032
INFO: task syz-executor.1:29872 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.1 D27008 29872 8133 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
dev_ioctl+0x19d/0xc50 net/core/dev_ioctl.c:487
sock_do_ioctl+0x178/0x300 net/socket.c:1038
sock_ioctl+0x2ef/0x5d0 net/socket.c:1135
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fd9c6e63669
Code: Bad RIP value.
RSP: 002b:00007fd9c57d7168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd9c6f84f80 RCX: 00007fd9c6e63669
RDX: 0000000020000040 RSI: 0000000000008914 RDI: 000000000000000a
RBP: 00007fd9c6ebe560 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcda62f61f R14: 00007fd9c57d7300 R15: 0000000000022000
INFO: task syz-executor.1:29892 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.1 D29920 29892 8133 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
dev_ioctl+0x3a2/0xc50 net/core/dev_ioctl.c:441
sock_do_ioctl+0x178/0x300 net/socket.c:1038
sock_ioctl+0x2ef/0x5d0 net/socket.c:1135
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fd9c6e63669
Code: Bad RIP value.
RSP: 002b:00007fd9c57b6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd9c6f85050 RCX: 00007fd9c6e63669
RDX: 0000000020000680 RSI: 0000000000008923 RDI: 000000000000000a
RBP: 00007fd9c6ebe560 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcda62f61f R14: 00007fd9c57b6300 R15: 0000000000022000
INFO: task syz-executor.2:29887 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.2 D28752 29887 8127 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
rtnl_lock net/core/rtnetlink.c:77 [inline]
rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:661
___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
__sys_sendmsg net/socket.c:2265 [inline]
__do_sys_sendmsg net/socket.c:2274 [inline]
__se_sys_sendmsg net/socket.c:2272 [inline]
__x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fdd1295d669
Code: Bad RIP value.
RSP: 002b:00007fdd1126e168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fdd12a7f1f0 RCX: 00007fdd1295d669
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 00007fdd129b8560 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcad8997af R14: 00007fdd1126e300 R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1570:
#0: 00000000146fb739 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
3 locks held by kworker/1:2/3497:
#0: 0000000098ccdd75 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 0000000076166d9d (cfg80211_disconnect_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 000000003fbf1204 (rtnl_mutex){+.+.}, at: disconnect_work+0x18/0x200 net/wireless/sme.c:664
1 lock held by in:imklog/7802:
#0: 000000003fc32e03 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
4 locks held by syz-executor.4/29873:
2 locks held by syz-executor.4/29890:
#0: 00000000b9d5bd21 (cb_lock){++++}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:637
#1: 000000003411ef41 (genl_mutex){+.+.}, at: genl_lock net/netlink/genetlink.c:33 [inline]
#1: 000000003411ef41 (genl_mutex){+.+.}, at: genl_rcv_msg+0x12f/0x160 net/netlink/genetlink.c:625
2 locks held by syz-executor.1/29864:
#0: 0000000034296559 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline]
#0: 0000000034296559 (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598
#1: 000000003fbf1204 (rtnl_mutex){+.+.}, at: ip_mc_drop_socket+0x89/0x260 net/ipv4/igmp.c:2702
1 lock held by syz-executor.1/29872:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x19d/0xc50 net/core/dev_ioctl.c:487
1 lock held by syz-executor.1/29892:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x3a2/0xc50 net/core/dev_ioctl.c:441
1 lock held by syz-executor.2/29887:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.0/29923:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: do_ip_setsockopt.constprop.0+0x11c/0x3ba0 net/ipv4/ip_sockglue.c:642
1 lock held by syz-executor.0/29932:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: do_ip_setsockopt.constprop.0+0x11c/0x3ba0 net/ipv4/ip_sockglue.c:642
1 lock held by syz-executor.0/29935:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x19d/0xc50 net/core/dev_ioctl.c:487
1 lock held by syz-executor.0/29938:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x3a2/0xc50 net/core/dev_ioctl.c:441
1 lock held by syz-executor.5/29926:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: do_ip_setsockopt.constprop.0+0x11c/0x3ba0 net/ipv4/ip_sockglue.c:642
1 lock held by syz-executor.5/29931:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: do_ip_setsockopt.constprop.0+0x11c/0x3ba0 net/ipv4/ip_sockglue.c:642
1 lock held by syz-executor.5/29934:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x19d/0xc50 net/core/dev_ioctl.c:487
1 lock held by syz-executor.5/29937:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x3a2/0xc50 net/core/dev_ioctl.c:441
1 lock held by syz-executor.3/29928:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: do_ip_setsockopt.constprop.0+0x11c/0x3ba0 net/ipv4/ip_sockglue.c:642
1 lock held by syz-executor.3/29933:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: do_ip_setsockopt.constprop.0+0x11c/0x3ba0 net/ipv4/ip_sockglue.c:642
1 lock held by syz-executor.3/29936:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x19d/0xc50 net/core/dev_ioctl.c:487
1 lock held by syz-executor.3/29939:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: dev_ioctl+0x3a2/0xc50 net/core/dev_ioctl.c:441
1 lock held by syz-executor.4/29944:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.2/29947:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.1/29948:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.0/29980:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.5/29983:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.3/29984:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
3 locks held by kworker/1:0/30008:
#0: 00000000ad168172 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 000000000644f809 ((addr_chk_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 000000003fbf1204 (rtnl_mutex){+.+.}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4476
1 lock held by syz-executor.4/30010:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.2/30012:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.1/30014:
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000003fbf1204 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779

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

NMI backtrace for cpu 0
CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9467 Comm: kworker/u4:6 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Workqueue: bat_events batadv_nc_worker
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline]
RIP: 0010:lock_acquire+0x1ec/0x3c0 kernel/locking/lockdep.c:3911
Code: 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 b7 01 00 00 48 83 3d 09 2e a6 08 00 0f 84 2a 01 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b
RSP: 0018:ffff88806a98fc58 EFLAGS: 00000286
RAX: 1ffffffff13e3051 RBX: ffff8880a0e7c5c0 RCX: c2cc60ee0328b757
RDX: dffffc0000000000 RSI: 000000005a4ba51f RDI: 0000000000000286
RBP: ffffffff89f85fa0 R08: 00000000e9a03af8 R09: 0000000000000002
R10: ffff8880a0e7ce98 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00230b000 CR3: 0000000096ba4000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:242 [inline]
rcu_read_lock include/linux/rcupdate.h:627 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline]
batadv_nc_worker+0x12d/0xd50 net/batman-adv/network-coding.c:730
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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