BUG: corrupted list in nf_tables_commit

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: db5b9190 Linux 4.19.96
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14d5b821e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=7a24894346f71303
dashboard link: https://syzkaller.appspot.com/bug?extid=5d664cfac14aa11c1da4
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15232659e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109fc235e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5d664c...@syzkaller.appspotmail.com

audit: type=1400 audit(1579140397.192:38): avc: denied { write } for
pid=8245 comm="syz-executor412"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tclass=netlink_netfilter_socket permissive=1
list_del corruption, ffff88809e449200->prev is LIST_POISON2
(dead000000000200)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:48!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8246 Comm: syz-executor412 Not tainted 4.19.96-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__list_del_entry_valid.cold+0x37/0x4f lib/list_debug.c:48
Code: eb fd 0f 0b 4c 89 ea 4c 89 f6 48 c7 c7 a0 2b eb 87 e8 e0 58 eb fd 0f
0b 4c 89 e2 4c 89 f6 48 c7 c7 00 2c eb 87 e8 cc 58 eb fd <0f> 0b 4c 89 f6
48 c7 c7 c0 2c eb 87 e8 bb 58 eb fd 0f 0b 90 90 90
RSP: 0018:ffff88807883f4a0 EFLAGS: 00010282
RAX: 000000000000004e RBX: ffff88809e449200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81558bc6 RDI: ffffed100f107e86
RBP: ffff88807883f4b8 R08: 000000000000004e R09: ffffed1015d25079
R10: ffffed1015d25078 R11: ffff8880ae9283c7 R12: dead000000000200
R13: ffff88809a9b7b80 R14: ffff88809e449200 R15: 0000000000000001
FS: 000000000145d880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020003ac0 CR3: 000000008c1ff000 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_rcu include/linux/rculist.h:130 [inline]
nf_tables_commit+0x19d0/0x41a0 net/netfilter/nf_tables_api.c:6573
nfnetlink_rcv_batch+0xcf6/0x1750 net/netfilter/nfnetlink.c:482
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:540 [inline]
nfnetlink_rcv+0x3ed/0x460 net/netfilter/nfnetlink.c:558
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x53a/0x730 net/netlink/af_netlink.c:1343
netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:632
___sys_sendmsg+0x803/0x920 net/socket.c:2115
__sys_sendmsg+0x105/0x1d0 net/socket.c:2153
__do_sys_sendmsg net/socket.c:2162 [inline]
__se_sys_sendmsg net/socket.c:2160 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2160
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441aa9
Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 9b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcfce1ff58 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441aa9
RDX: 0000000000000042 RSI: 0000000020003ac0 RDI: 0000000000000003
RBP: 0000000000006f6c R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 00000000004028d0
R13: 0000000000402960 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 17d896556c622024 ]---
RIP: 0010:__list_del_entry_valid.cold+0x37/0x4f lib/list_debug.c:48
Code: eb fd 0f 0b 4c 89 ea 4c 89 f6 48 c7 c7 a0 2b eb 87 e8 e0 58 eb fd 0f
0b 4c 89 e2 4c 89 f6 48 c7 c7 00 2c eb 87 e8 cc 58 eb fd <0f> 0b 4c 89 f6
48 c7 c7 c0 2c eb 87 e8 bb 58 eb fd 0f 0b 90 90 90
RSP: 0018:ffff88807883f4a0 EFLAGS: 00010282
RAX: 000000000000004e RBX: ffff88809e449200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81558bc6 RDI: ffffed100f107e86
RBP: ffff88807883f4b8 R08: 000000000000004e R09: ffffed1015d25079
R10: ffffed1015d25078 R11: ffff8880ae9283c7 R12: dead000000000200
R13: ffff88809a9b7b80 R14: ffff88809e449200 R15: 0000000000000001
FS: 000000000145d880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020003ac0 CR3: 000000008c1ff000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot suspects this bug was fixed by commit:

commit 8260ce5aeee4d7c4a6305e469edeae1066de2800
Author: Florian Westphal <f...@strlen.de>
Date: Thu Jan 16 11:03:01 2020 +0000

netfilter: nf_tables: fix flowtable list del corruption

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106389e9e00000
start commit: db5b9190 Linux 4.19.96
git tree: linux-4.19.y

kernel config: https://syzkaller.appspot.com/x/.config?x=7a24894346f71303
dashboard link: https://syzkaller.appspot.com/bug?extid=5d664cfac14aa11c1da4

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1445b8d1e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b14421e00000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: netfilter: nf_tables: fix flowtable list del corruption

For information about bisection process see: https://goo.gl/tpsmEJ#bisection