WARNING in tcp

WARNING in tcp_ack
Status: fixed on 2020/02/18 14:31
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 90d72256addf gtp: fix bad unlock balance in gtp_encap_enable_socket
First crash: 696d, last: 696d

Cause bisection: introduced by (bisect log) :
commit e198987e7dd7d3645a53875151cd6f8fc425b706
Author: Taehee Yoo <ap420073@gmail.com>
Date: Tue Jul 2 15:20:51 2019 +0000

gtp: fix suspicious RCU usage

Crash: WARNING in tcp_ack (log)
Repro: C syz .config

Sample crash report:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 9988 at include/net/sock.h:1578 sock_owned_by_me include/net/sock.h:1578 [inline]
WARNING: CPU: 0 PID: 9988 at include/net/sock.h:1578 sock_owned_by_me include/net/sock.h:1575 [inline]
WARNING: CPU: 0 PID: 9988 at include/net/sock.h:1578 tcp_snd_una_update net/ipv4/tcp_input.c:3355 [inline]
WARNING: CPU: 0 PID: 9988 at include/net/sock.h:1578 tcp_ack_update_window net/ipv4/tcp_input.c:3408 [inline]
WARNING: CPU: 0 PID: 9988 at include/net/sock.h:1578 tcp_ack+0x2f36/0x5a00 net/ipv4/tcp_input.c:3663
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9988 Comm: syz-executor253 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x3e kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:sock_owned_by_me include/net/sock.h:1578 [inline]
RIP: 0010:sock_owned_by_me include/net/sock.h:1575 [inline]
RIP: 0010:tcp_snd_una_update net/ipv4/tcp_input.c:3355 [inline]
RIP: 0010:tcp_ack_update_window net/ipv4/tcp_input.c:3408 [inline]
RIP: 0010:tcp_ack+0x2f36/0x5a00 net/ipv4/tcp_input.c:3663
Code: d0 7c 08 84 d2 0f 85 9c 22 00 00 44 8b 2d b6 0c e3 03 31 ff 44 89 ee e8 28 7d dc fa 45 85 ed 0f 84 28 d9 ff ff e8 9a 7b dc fa <0f> 0b e9 1c d9 ff ff 48 c7 c3 ff ff ff ff 48 c7 85 70 fe ff ff ff
RSP: 0018:ffffc90001da6b70 EFLAGS: 00010293
RAX: ffff8880a824e240 RBX: 0000000000000068 RCX: ffffffff8698ab48
RDX: 0000000000000000 RSI: ffffffff8698ab56 RDI: 0000000000000005
RBP: ffffc90001da6dd0 R08: ffff8880a824e240 R09: fffffbfff165eba8
R10: fffffbfff165eba7 R11: ffffffff8b2f5d3f R12: 0000000000000002
R13: 0000000000000001 R14: 0000000000002400 R15: ffff8880a179c140
 tcp_rcv_established+0x6dd/0x1e90 net/ipv4/tcp_input.c:5698
 tcp_v4_do_rcv+0x619/0x8d0 net/ipv4/tcp_ipv4.c:1562
 sk_backlog_rcv include/net/sock.h:954 [inline]
 __release_sock+0x129/0x390 net/core/sock.c:2437
 release_sock+0x59/0x1c0 net/core/sock.c:2953
 gtp_encap_enable_socket+0x146/0x400 drivers/net/gtp.c:830
 gtp_encap_enable drivers/net/gtp.c:852 [inline]
 gtp_newlink+0x9fc/0xc60 drivers/net/gtp.c:666
 __rtnl_newlink+0x109e/0x1790 net/core/rtnetlink.c:3305
 rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3363
 rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5424
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 ____sys_sendmsg+0x753/0x880 net/socket.c:2330
 ___sys_sendmsg+0x100/0x170 net/socket.c:2384
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x449529
Code: e8 8c 0f 03 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 fb 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fbbf32f0d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006e5a18 RCX: 0000000000449529
RDX: 0000000020000000 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 00000000006e5a10 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 00000000006e5a1c
R13: d8de18c65af65c00 R14: 6078ba41124867b9 R15: 88651f7f928a260c
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-root	2020/01/08 21:14	upstream	ae6088216ce4	ddc3e859	.config	log	report	syz	C
ci-upstream-net-kasan-gce	2020/01/08 07:00	net-next	1ece2fbe9b42	6738e0b3	.config	log	report	syz	C
ci-upstream-net-this-kasan-gce	2020/01/08 08:24	net	47240ba0cd09	6738e0b3	.config	log	report