KCSAN: data-race in udpv6_sendmsg / udpv6

KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg
Status: auto-closed as invalid on 2020/08/23 02:37
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 377d, last: 377d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg (3)				1	91d	91d	0/22	auto-closed as invalid on 2021/06/05 06:06
upstream	KCSAN: data-race in udpv6_sendmsg / udpv6_sendmsg (2)				1	329d	329d	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 0xffff88807a680e48 of 4 bytes by task 11432 on cpu 1:
 udpv6_sendmsg+0x14af/0x1780 net/ipv6/udp.c:1488
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:638
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 __sys_sendto+0x2ad/0x380 net/socket.c:1995
 __do_sys_sendto net/socket.c:2007 [inline]
 __se_sys_sendto net/socket.c:2003 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:2003
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88807a680e48 of 4 bytes by task 11456 on cpu 0:
 udpv6_sendmsg+0x1eb/0x1780 net/ipv6/udp.c:1268
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:638
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 sock_write_iter+0x1a1/0x200 net/socket.c:999
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x607/0x690 fs/read_write.c:578
 ksys_write+0xce/0x180 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11456 Comm: syz-executor.3 Not tainted 5.8.0-rc5-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	2020/07/19 02:30	upstream	6cf7ccba29dc	9c812472	.config	log	report