KCSAN: data-race in tcp_disconnect / tcp

KCSAN: data-race in tcp_disconnect / tcp_poll
Status: moderation: reported on 2020/12/11 11:24
Reported-by: syzbot+2326116798df66b56cd5@syzkaller.appspotmail.com
First crash: 68d, last: 34d

Sample crash report:

==================================================================
BUG: KCSAN: data-race in tcp_disconnect / tcp_poll

write to 0xffff88810e1896ea of 1 bytes by task 18252 on cpu 1:
 tcp_disconnect+0x4a4/0xd40 net/ipv4/tcp.c:2927
 __inet_stream_connect+0x543/0x710 net/ipv4/af_inet.c:713
 tcp_sendmsg_fastopen net/ipv4/tcp.c:1191 [inline]
 tcp_sendmsg_locked+0x2036/0x2130 net/ipv4/tcp.c:1233
 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1459
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 __sys_sendto+0x2a8/0x370 net/socket.c:1975
 __do_sys_sendto net/socket.c:1987 [inline]
 __se_sys_sendto net/socket.c:1983 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:1983
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810e1896ea of 1 bytes by task 18202 on cpu 0:
 tcp_poll+0x355/0x690 net/ipv4/tcp.c:568
 sock_poll+0x23e/0x260 net/socket.c:1244
 vfs_poll include/linux/poll.h:90 [inline]
 do_select+0x8b1/0xfc0 fs/select.c:534
 core_sys_select+0x408/0x690 fs/select.c:677
 kern_select fs/select.c:718 [inline]
 __do_sys_select fs/select.c:725 [inline]
 __se_sys_select+0x180/0x1c0 fs/select.c:722
 __x64_sys_select+0x63/0x70 fs/select.c:722
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18202 Comm: syz-executor.2 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Maintainers
ci2-upstream-kcsan-gce	2020/12/21 19:56	upstream	e37b12e4	04201c06	.config	log	report			info	andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, edumazet@google.com, john.fastabend@gmail.com, kafai@fb.com, kpsingh@kernel.org, kuba@kernel.org, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, yhs@fb.com, yoshfuji@linux-ipv6.org
ci2-upstream-kcsan-gce	2020/11/17 21:55	upstream	111e91a6	09323409	.config	log	report			info	andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, edumazet@google.com, john.fastabend@gmail.com, kafai@fb.com, kpsingh@chromium.org, kuba@kernel.org, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, yhs@fb.com, yoshfuji@linux-ipv6.org