syzbot

Dev nbd4: unable to read RDB block 0
 nbd4: unable to read partition table
list_del corruption, ffff8880abbee6b0->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
nbd4: partition table beyond EOD, truncated
kernel BUG at lib/list_debug.c:45!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 24548 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__list_del_entry_valid.cold+0x23/0x4a lib/list_debug.c:45
Code: e8 11 43 f7 ff 0f 0b 48 89 ee 48 c7 c7 40 e4 b3 88 e8 00 43 f7 ff 0f 0b 4c 89 ea 48 89 ee 48 c7 c7 80 e3 b3 88 e8 ec 42 f7 ff <0f> 0b 4c 89 e2 48 89 ee 48 c7 c7 e0 e3 b3 88 e8 d8 42 f7 ff 0f 0b
RSP: 0018:ffff888049e476b0 EFLAGS: 00010286
RAX: 000000000000004e RBX: 0000000000000005 RCX: 0000000000000000
RDX: 000000000001a9a9 RSI: ffffffff814dff01 RDI: ffffed10093c8ec8
RBP: ffff8880abbee6b0 R08: 000000000000004e R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: dead000000000200
R13: dead000000000100 R14: ffff8880abbee6b8 R15: ffffffff87c31bd0
FS:  00007f49c8e0a700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9f198d741 CR3: 00000000a0eaf000 CR4: 00000000003406f0
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+0x71/0x230 net/9p/trans_fd.c:737
 p9_client_flush+0x397/0x490 net/9p/client.c:690
 p9_client_rpc+0x1203/0x1440 net/9p/client.c:797
 p9_client_version net/9p/client.c:968 [inline]
 p9_client_create+0xa88/0x12e0 net/9p/client.c:1068
 v9fs_session_init+0x1dd/0x1770 fs/9p/v9fs.c:421
 v9fs_mount+0x73/0x910 fs/9p/vfs_super.c:135
 mount_fs+0xa3/0x310 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2492 [inline]
 do_mount+0x115c/0x2f50 fs/namespace.c:2822
 ksys_mount+0xcf/0x130 fs/namespace.c:3038
 __do_sys_mount fs/namespace.c:3052 [inline]
 __se_sys_mount fs/namespace.c:3049 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3049
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f49ca4d6e99
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f49c8e0a168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f49ca5ea100 RCX: 00007f49ca4d6e99
RDX: 0000000020000200 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00007f49ca530ff1 R08: 0000000020000180 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffead9950af R14: 00007f49c8e0a300 R15: 0000000000022000
Modules linked in:
---[ end trace 60c40e63d0462f54 ]---
RIP: 0010:__list_del_entry_valid.cold+0x23/0x4a lib/list_debug.c:45
Code: e8 11 43 f7 ff 0f 0b 48 89 ee 48 c7 c7 40 e4 b3 88 e8 00 43 f7 ff 0f 0b 4c 89 ea 48 89 ee 48 c7 c7 80 e3 b3 88 e8 ec 42 f7 ff <0f> 0b 4c 89 e2 48 89 ee 48 c7 c7 e0 e3 b3 88 e8 d8 42 f7 ff 0f 0b
RSP: 0018:ffff888049e476b0 EFLAGS: 00010286
RAX: 000000000000004e RBX: 0000000000000005 RCX: 0000000000000000
RDX: 000000000001a9a9 RSI: ffffffff814dff01 RDI: ffffed10093c8ec8
RBP: ffff8880abbee6b0 R08: 000000000000004e R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: dead000000000200
R13: dead000000000100 R14: ffff8880abbee6b8 R15: ffffffff87c31bd0
FS:  00007f49c8e0a700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9f198d741 CR3: 00000000a0eaf000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400