KCSAN: data-race in inet_send_prepare / udp_lib_get

KCSAN: data-race in inet_send_prepare / udp_lib_get_port (3)
Status: internal: reported on 2021/06/07 12:32
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: 47d, last: 44d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in inet_send_prepare / udp_lib_get_port (2)				1	99d	99d	0/22	auto-closed as invalid on 2021/05/21 15:38
upstream	KCSAN: data-race in inet_send_prepare / udp_lib_get_port				1	623d	623d	0/22	closed as invalid on 2019/11/19 14:44

Sample crash report:

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

write to 0xffff88812e04a00e of 2 bytes by task 16676 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_dgram_connect+0x12a/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

read to 0xffff88812e04a00e of 2 bytes by task 16693 on cpu 0:
 inet_send_prepare+0x21/0x210 net/ipv4/af_inet.c:806
 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

value changed: 0x0000 -> 0xb52b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16693 Comm: syz-executor.3 Not tainted 5.13.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/06/10 11:44	upstream	cd1245d75ce9	1ba81399	.config	log	report	info	KCSAN: data-race in inet_send_prepare / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/06/08 22:07	upstream	4c8684fe555e	5c2fe346	.config	log	report	info	KCSAN: data-race in inet_send_prepare / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/06/08 00:19	upstream	614124bea77e	b718257f	.config	log	report	info	KCSAN: data-race in inet_send_prepare / udp_lib_get_port
ci2-upstream-kcsan-gce	2021/06/06 22:32	upstream	decad3e1d1ed	500c2339	.config	log	report	info	KCSAN: data-race in inet_send_prepare / udp_lib_get_port