syzbot


INFO: task hung in genl_rcv_msg

Status: fixed on 2020/02/16 23:53
Reported-by: syzbot+35aba01a785cf6164fa4@syzkaller.appspotmail.com
Fix commit: 24070b40926b tcp: clear tp->total_retrans in tcp_disconnect()
First crash: 939d, last: 939d

Fix bisection: fixed by (bisect log) :
commit 24070b40926b42c35ca0649f44711cad5da0cf96
Author: Eric Dumazet <edumazet@google.com>
Date: Fri Jan 31 17:14:47 2020 +0000

  tcp: clear tp->total_retrans in tcp_disconnect()

similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in genl_rcv_msg syz error 15 164d 1199d 0/1 upstream: reported syz repro on 2019/05/02 15:34
upstream INFO: task hung in genl_rcv_msg syz done error 643 21d 1398d 0/23 upstream: reported syz repro on 2018/10/15 08:06
linux-4.14 INFO: task hung in genl_rcv_msg (2) 6 634d 822d 0/1 auto-closed as invalid on 2021/03/17 23:44

Sample crash report:
INFO: task syz-executor.2:26728 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28928 26728   7378 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007ff78a1099c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff78a109a58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007ff78a109a00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007ff78a109a40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bf2c
INFO: task syz-executor.2:26733 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28928 26733   7378 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007ff78a0e89c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff78a0e8a58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007ff78a0e8a00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007ff78a0e8a40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bfd4
INFO: task syz-executor.3:26730 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D28928 26730   7373 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007fa0a941e9c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fa0a941ea58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007fa0a941ea00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007fa0a941ea40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bf2c
INFO: task syz-executor.3:26737 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D28928 26737   7373 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007fa0a93fd9c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fa0a93fda58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007fa0a93fda00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007fa0a93fda40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bfd4
INFO: task syz-executor.4:26729 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28928 26729   7382 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007f5475b769c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5475b76a58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007f5475b76a00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f5475b76a40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bf2c
INFO: task syz-executor.4:26734 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28928 26734   7382 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007f5475b559c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5475b55a58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007f5475b55a00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f5475b55a40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bfd4
INFO: task syz-executor.5:26732 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D28928 26732   7376 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007f8f9ba8b9c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8f9ba8ba58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007f8f9ba8ba00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f8f9ba8ba40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bf2c
INFO: task syz-executor.5:26736 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D28928 26736   7376 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007f8f9ba6a9c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8f9ba6aa58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007f8f9ba6aa00 RDI: 0000000000000003
RBP: 0000000000000003 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f8f9ba6aa40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bfd4
INFO: task syz-executor.0:26731 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28928 26731   7383 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007f99dbbed9c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f99dbbeda58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007f99dbbeda00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f99dbbeda40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bf2c
INFO: task syz-executor.0:26735 blocked for more than 140 seconds.
      Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28848 26735   7383 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
 schedule+0x92/0x1c0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 genl_lock net/netlink/genetlink.c:33 [inline]
 genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414cb1
RSP: 002b:00007f99dbbcc9c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f99dbbcca58 RCX: 0000000000414cb1
RDX: 0000000000000000 RSI: 00007f99dbbcca00 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000000000b R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f99dbbcca40
R13: 0000000000000b48 R14: 00000000004d5630 R15: 000000000075bfd4

Showing all locks held in the system:
1 lock held by khungtaskd/1056:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81489c18>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
2 locks held by getty/7332:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7333:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7334:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7335:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7336:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7337:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7338:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.2/26728:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.2/26733:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.3/26730:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.3/26737:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.4/26729:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.4/26734:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.5/26732:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.5/26736:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.0/26731:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623
2 locks held by syz-executor.0/26735:
 #0:  (cb_lock){++++}, at: [<ffffffff853fd56a>] genl_rcv+0x1a/0x40 net/netlink/genetlink.c:635
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_lock net/netlink/genetlink.c:33 [inline]
 #1:  (genl_mutex){+.+.}, at: [<ffffffff85400db9>] genl_rcv_msg+0x119/0x150 net/netlink/genetlink.c:623

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

NMI backtrace for cpu 1
CPU: 1 PID: 1056 Comm: khungtaskd Not tainted 4.14.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e7/0xb90 kernel/hung_task.c:274
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7397 Comm: kworker/u4:1 Not tainted 4.14.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
task: ffff88808681c380 task.stack: ffff888098e98000
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:774 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:796 [inline]
RIP: 0010:lock_acquire+0x8b/0x430 kernel/locking/lockdep.c:3989
RSP: 0018:ffff888098e9fc90 EFLAGS: 00000246
RAX: 1ffffffff0fe2d28 RBX: ffff88808681c380 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff88808681cbfc
RBP: ffff888098e9fcd8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff87f872a0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000b4e978 CR3: 000000009577a000 CR4: 00000000001406f0
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:629 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline]
 batadv_nc_worker+0x107/0x6d0 net/batman-adv/network-coding.c:726
 process_one_work+0x863/0x1600 kernel/workqueue.c:2114
 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 7c 08 00 00 85 f6 0f 85 83 01 00 00 48 c7 c0 40 69 f1 87 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 6a 03 00 00 <48> 83 3d dd f2 a8 06 00 0f 84 a5 02 00 00 9c 58 0f 1f 44 00 00 

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/01/17 19:33 linux-4.14.y c04fc6fa5c96 3de7aabb .config log report syz
ci2-linux-4-14 2020/01/17 16:42 linux-4.14.y c04fc6fa5c96 3de7aabb .config log report