BUG: corrupted list in p9_fd

BUG: corrupted list in p9_fd_cancelled
Status: upstream: reported syz repro on 2019/10/18 05:34
Reported-by: syzbot+4223d5758fb837a10a31@syzkaller.appspotmail.com
First crash: 30d, last: 30d

similar bugs (3):
Kernel	Title	Repro	Bisected	Count	Last	Reported	Patched	Status
upstream	BUG: corrupted list in p9_fd_cancelled (2)	syz	cause+fix	2	32d	80d	0/14	upstream: reported syz repro on 2019/08/29 03:58
linux-4.19	BUG: corrupted list in p9_fd_cancelled	syz		2	4d12h	67d	0/1	upstream: reported syz repro on 2019/09/11 07:16
upstream	BUG: corrupted list in p9_fd_cancelled			16	388d	489d	0/14	auto-closed as invalid on 2019/04/23 06:51

Sample crash report:

9pnet: Insufficient options for proto=fd
list_del corruption, ffff88804ebebda8->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:45!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 25265 Comm: syz-executor.1 Not tainted 4.14.150 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809b73c140 task.stack: ffff88804eac8000
RIP: 0010:__list_del_entry_valid.cold+0x23/0x4f lib/list_debug.c:45
kobject: 'loop0' (ffff8880a492eee0): kobject_uevent_env
RSP: 0018:ffff88804eacf780 EFLAGS: 00010286
RAX: 000000000000004e RBX: ffff88804ebebd80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff866d10e0 RDI: ffffed1009d59ee6
RBP: ffff88804eacf798 R08: 000000000000004e R09: ffff88809b73c9e0
R10: 0000000000000000 R11: 0000000000000000 R12: dead000000000200
R13: dead000000000100 R14: ffff88804ebebda8 R15: ffff88804ebebdf0
FS:  00007f4d7ae56700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009e5a8000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_del_entry include/linux/list.h:117 [inline]
 list_del include/linux/list.h:125 [inline]
 p9_fd_cancelled+0x34/0x190 net/9p/trans_fd.c:719
 p9_client_flush+0x1b5/0x210 net/9p/client.c:698
 p9_client_rpc+0xf12/0x1180 net/9p/client.c:807
kobject: 'loop0' (ffff8880a492eee0): fill_kobj_path: path = '/devices/virtual/block/loop0'
 p9_client_version net/9p/client.c:980 [inline]
 p9_client_create+0x997/0x1120 net/9p/client.c:1088
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
kobject: 'loop3' (ffff8880a4a189e0): kobject_uevent_env
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x97/0x2a1 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
kobject: 'loop3' (ffff8880a4a189e0): fill_kobj_path: path = '/devices/virtual/block/loop3'
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a59
RSP: 002b:00007f4d7ae55c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459a59
RDX: 0000000020000100 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000020000600 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4d7ae566d4
R13: 00000000004c6252 R14: 00000000004db3a8 R15: 00000000ffffffff
Code: e6 e8 94 c2 72 
kobject: 'loop3' (ffff8880a4a189e0): kobject_uevent_env
fe 
kobject: 'loop3' (ffff8880a4a189e0): fill_kobj_path: path = '/devices/virtual/block/loop3'
0f 0b 4c 89 f6 48 c7 c7 80 35 9d 86 e8 83 c2 72 fe 0f 0b 4c 89 ea 4c 89 f6 48 c7 c7 c0 34 9d 86 e8 6f c2 72 fe <0f> 0b 4c 89 e2 4c 89 f6 48 c7 c7 20 35 9d 86 e8 5b c2 72 
kobject: 'loop0' (ffff8880a492eee0): kobject_uevent_env
fe 0f 
RIP: __list_del_entry_valid.cold+0x23/0x4f lib/list_debug.c:45 RSP: ffff88804eacf780
---[ end trace 0146b3a2a12e67c7 ]---
kobject: 'loop0' (ffff8880a492eee0): fill_kobj_path: path = '/devices/virtual/block/loop0'

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci2-linux-4-14	2019/10/18 04:33	linux-4.14.y	b98aebd2	8c88c9c1	.config	log	report	syz		davem@davemloft.net, ericvh@gmail.com, linux-kernel@vger.kernel.org, lucho@ionkov.net, netdev@vger.kernel.org, rminnich@sandia.gov, v9fs-developer@lists.sourceforge.net