KCSAN: data-race in sock_alloc_send_pskb / unix_dgram

KCSAN: data-race in sock_alloc_send_pskb / unix_dgram_connect (2)
Status: auto-closed as invalid on 2021/02/22 18:25
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 195d, last: 195d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_dgram_connect (3)				15	49d	137d	0/22	auto-closed as invalid on 2021/07/18 16:15
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_dgram_connect				1	256d	233d	0/22	auto-closed as invalid on 2020/12/25 11:44

Sample crash report:

==================================================================
BUG: KCSAN: data-race in sock_alloc_send_pskb / unix_dgram_connect

write to 0xffff888037869230 of 4 bytes by task 29203 on cpu 0:
 unix_dgram_disconnected net/unix/af_unix.c:486 [inline]
 unix_dgram_connect+0x792/0x860 net/unix/af_unix.c:1190
 __sys_connect_file net/socket.c:1835 [inline]
 __sys_connect+0x245/0x280 net/socket.c:1852
 __do_sys_connect net/socket.c:1862 [inline]
 __se_sys_connect net/socket.c:1859 [inline]
 __x64_sys_connect+0x3d/0x50 net/socket.c:1859
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888037869230 of 4 bytes by task 29206 on cpu 1:
 sock_error include/net/sock.h:2235 [inline]
 sock_alloc_send_pskb+0xe4/0x4e0 net/core/sock.c:2328
 unix_dgram_sendmsg+0x485/0x1660 net/unix/af_unix.c:1670
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x352/0x4c0 net/socket.c:2345
 ___sys_sendmsg net/socket.c:2399 [inline]
 __sys_sendmmsg+0x335/0x4b0 net/socket.c:2489
 __do_sys_sendmmsg net/socket.c:2518 [inline]
 __se_sys_sendmmsg net/socket.c:2515 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2515
 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: 1 PID: 29206 Comm: syz-executor.5 Not tainted 5.11.0-rc4-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	2021/01/18 18:23	upstream	19c329f68089	63631df1	.config	log	report			info	KCSAN: data-race in sock_alloc_send_pskb / unix_dgram_connect