RBP: 000000000072bea0 R08: 00000000000000cb R09: 0000000000000000
R10: 0000000020000080 R11: 0000000000000246 R12: 0000000000000014
R13: 000000000000055e R14: 00000000006fc170 R15: 0000000000000004
device bridge_slave_1 left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
IP: __list_del_entry_valid+0xd1/0x440 lib/list_debug.c:51
PGD 800000019874a067 P4D 800000019874a067 PUD 1cc08a067 PMD 0 
Oops: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 15658 Comm: syz-executor0 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__list_del_entry_valid+0xd1/0x440 lib/list_debug.c:51
RSP: 0018:ffff8801ca06f0c0 EFLAGS: 00010046
RAX: ffff88014a4077e0 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88014b5a77e0 RSI: aaaaaaaaaaaab000 RDI: ffffea0000000000
RBP: ffff8801ca06f118 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007ff12fdcc700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000019a4ac000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 __list_del_entry include/linux/list.h:117 [inline]
 list_del_init include/linux/list.h:159 [inline]
 delete_and_unsubscribe_port+0x1a5/0x940 sound/core/seq/seq_ports.c:550
 clear_subscriber_list+0xaa4/0xd80 sound/core/seq/seq_ports.c:240
 port_delete sound/core/seq/seq_ports.c:270 [inline]
 snd_seq_delete_port+0x574/0x780 sound/core/seq/seq_ports.c:303
 snd_seq_ioctl_delete_port+0x107/0x250 sound/core/seq/seq_clientmgr.c:1325
 snd_seq_kernel_client_ctl+0x555/0x5d0 sound/core/seq/seq_clientmgr.c:2360
 snd_seq_event_port_detach+0xe3/0x140 sound/core/seq/seq_ports.c:705
 delete_port sound/core/seq/oss/seq_oss_init.c:354 [inline]
 snd_seq_oss_release+0x1ca/0x3d0 sound/core/seq/oss/seq_oss_init.c:433
 odev_release+0x85/0xe0 sound/core/seq/oss/seq_oss.c:153
 __fput+0x49e/0xa10 fs/file_table.c:209
 ____fput+0x37/0x40 fs/file_table.c:243
 task_work_run+0x243/0x2c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x10e1/0x38d0 kernel/exit.c:867
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0x1320/0x1f20 kernel/signal.c:2469
 do_signal+0xb8/0x1c80 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop arch/x86/entry/common.c:162 [inline]
 prepare_exit_to_usermode+0x271/0x3a0 arch/x86/entry/common.c:196
 syscall_return_slowpath+0xe9/0x700 arch/x86/entry/common.c:265
 do_syscall_64+0x36d/0x430 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455979
RSP: 002b:00007ff12fdcbce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000072c028 RCX: 0000000000455979
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072c028
RBP: 000000000072c028 R08: 0000000000000000 R09: 000000000072c000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000a3e81f R14: 00007ff12fdcc9c0 R15: 0000000000000002
Code: 15 4c 89 f8 4c 31 f0 4c 89 e1 48 f7 d1 48 21 c1 0f 84 76 01 00 00 4d 39 f7 0f 84 7e 01 00 00 41 89 de 4d 85 e4 0f 85 01 02 00 00 <4d> 8b 27 4c 89 ff e8 e4 79 cb fd 48 8b 18 44 8b 3a 48 89 d8 48 
RIP: __list_del_entry_valid+0xd1/0x440 lib/list_debug.c:51 RSP: ffff8801ca06f0c0
CR2: 0000000000000000
---[ end trace a77f3ca0cb701cc6 ]---