KCSAN: data-race in udpv6_sendmsg / udpv6

KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg (3)
Status: auto-closed as invalid on 2021/06/05 06:06
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 90d, last: 90d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg				1	376d	376d	0/22	auto-closed as invalid on 2020/08/23 02:37
upstream	KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg (2)				1	328d	328d	0/22	auto-closed as invalid on 2020/10/10 02:50

Sample crash report:

==================================================================
BUG: KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg

write to 0xffff888155ef7430 of 4 bytes by task 18068 on cpu 0:
 udpv6_sendmsg+0x15bc/0x16b0 net/ipv6/udp.c:1548
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:642
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 __sys_sendto+0x2a8/0x370 net/socket.c:1977
 __do_sys_sendto net/socket.c:1989 [inline]
 __se_sys_sendto net/socket.c:1985 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:1985
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888155ef7430 of 4 bytes by task 18069 on cpu 1:
 udpv6_sendmsg+0x201/0x16b0 net/ipv6/udp.c:1328
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:642
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmmsg+0x315/0x4b0 net/socket.c:2490
 __do_sys_sendmmsg net/socket.c:2519 [inline]
 __se_sys_sendmmsg net/socket.c:2516 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18069 Comm: syz-executor.2 Tainted: G        W         5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2021/05/01 06:02	upstream	65c61de9d090	77e2b668	.config	log	report			info	KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg