KCSAN: data-race in inet_dgram_connect / udp_lib_get

KCSAN: data-race in inet_dgram_connect / udp_lib_get_port (5)
Status: internal: reported on 2021/06/10 14:00
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: dcd01eeac144 inet: annotate data race in inet_send_prepare() and inet_dgram_connect()
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce ci-upstream-kmsan-gce-386 ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-arm32]
First crash: 124d, last: 56d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port	1	635d	635d	0/22	closed as invalid on 2019/11/19 13:44
upstream	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port (2)	3	603d	609d	0/22	auto-closed as invalid on 2020/02/05 16:37
upstream	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port (3)	1	259d	224d	0/22	auto-closed as invalid on 2020/12/25 11:24
upstream	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port (4)	1	172d	172d	0/22	auto-closed as invalid on 2021/03/07 18:58

Sample crash report:

==================================================================
BUG: KCSAN: data-race in inet_dgram_connect / udp_lib_get_port

write to 0xffff888135c095ce of 2 bytes by task 31802 on cpu 1:
 udp_lib_get_port+0x4b2/0xe20 net/ipv4/udp.c:308
 udp_v6_get_port+0x5e/0x70 net/ipv6/udp.c:89
 inet_autobind net/ipv4/af_inet.c:183 [inline]
 inet_send_prepare+0xd0/0x210 net/ipv4/af_inet.c:807
 inet6_sendmsg+0x29/0x80 net/ipv6/af_inet6.c:639
 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

read to 0xffff888135c095ce of 2 bytes by task 31800 on cpu 0:
 inet_dgram_connect+0x6d/0x180 net/ipv4/af_inet.c:578
 __sys_connect_file net/socket.c:1837 [inline]
 __sys_connect+0x245/0x280 net/socket.c:1854
 __do_sys_connect net/socket.c:1864 [inline]
 __se_sys_connect net/socket.c:1861 [inline]
 __x64_sys_connect+0x3d/0x50 net/socket.c:1861
 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: 0 PID: 31800 Comm: syz-executor.3 Tainted: G        W         5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (6):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/05/28 14:16	upstream	97e5bf604b7a	858ea628	.config	log	report	info	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/05/24 23:28	upstream	c4681547bcce	3c7fef33	.config	log	report	info	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/04/28 03:12	upstream	e359bce39d90	805b5003	.config	log	report	info	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/04/26 16:13	upstream	9f4ad9e425a1	805b5003	.config	log	report	info	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/04/24 07:08	upstream	8db5efb83fa9	17f0b706	.config	log	report	info	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/03/21 02:38	upstream	812da4d39463	17810eae	.config	log	report	info	KCSAN: data-race in inet_dgram_connect / udp_lib_get_port