KCSAN: data-race in sock_alloc_send_pskb / unix

KCSAN: data-race in sock_alloc_send_pskb / unix_shutdown (2)
Status: auto-closed as invalid on 2021/07/29 06:04
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 116d, last: 116d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_shutdown				1	474d	474d	0/22	auto-closed as invalid on 2020/08/04 22:26

Sample crash report:

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

write to 0xffff88813d0c9e6a of 1 bytes by task 25277 on cpu 1:
 unix_shutdown+0x1dd/0x3b0 net/unix/af_unix.c:2533
 __sys_shutdown_sock net/socket.c:2176 [inline]
 __sys_shutdown net/socket.c:2188 [inline]
 __do_sys_shutdown net/socket.c:2196 [inline]
 __se_sys_shutdown+0xf6/0x140 net/socket.c:2194
 __x64_sys_shutdown+0x2d/0x40 net/socket.c:2194
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813d0c9e6a of 1 bytes by task 25850 on cpu 0:
 sock_alloc_send_pskb+0x113/0x4e0 net/core/sock.c:2349
 unix_dgram_sendmsg+0x478/0x1610 net/unix/af_unix.c:1672
 unix_seqpacket_sendmsg+0xcc/0x110 net/unix/af_unix.c:2056
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2337
 __sys_sendmsg_sock+0x25/0x30 net/socket.c:2403
 io_sendmsg fs/io_uring.c:4372 [inline]
 io_issue_sqe+0x231a/0x6750 fs/io_uring.c:6140
 __io_queue_sqe+0xe9/0x360 fs/io_uring.c:6419
 io_queue_sqe fs/io_uring.c:6468 [inline]
 io_submit_sqe+0x1887/0x3360 fs/io_uring.c:6631
 io_submit_sqes+0x5bd/0xbd0 fs/io_uring.c:6739
 __do_sys_io_uring_enter fs/io_uring.c:9336 [inline]
 __se_sys_io_uring_enter+0x1e1/0xa80 fs/io_uring.c:9278
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:9278
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25850 Comm: syz-executor.0 Not tainted 5.13.0-rc7-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	2021/06/24 05:55	upstream	7266f2030eb0	fe4ab389	.config	log	report			info	KCSAN: data-race in sock_alloc_send_pskb / unix_shutdown