KCSAN: data-race in unix_dgram_connect / unix_dgram

KCSAN: data-race in unix_dgram_connect / unix_dgram_poll
Status: auto-closed as invalid on 2020/08/27 17:47
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 459d, last: 429d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in unix_dgram_connect / unix_dgram_poll (3)	4	206d	250d	0/22	auto-closed as invalid on 2021/04/07 19:26
upstream	KCSAN: data-race in unix_dgram_connect / unix_dgram_poll (5)	1	43d	43d	0/22	auto-closed as invalid on 2021/09/17 19:26
upstream	KCSAN: data-race in unix_dgram_connect / unix_dgram_poll (2)	3	311d	288d	0/22	auto-closed as invalid on 2020/12/25 10:44
upstream	KCSAN: data-race in unix_dgram_connect / unix_dgram_poll (4)	2	125d	141d	0/22	auto-closed as invalid on 2021/06/27 09:27

Sample crash report:

BUG: KCSAN: data-race in unix_dgram_connect / unix_dgram_poll

write to 0xffff8880a0b97a30 of 4 bytes by task 22155 on cpu 1:
 unix_dgram_disconnected net/unix/af_unix.c:486 [inline]
 unix_dgram_connect+0x750/0x820 net/unix/af_unix.c:1199
 __sys_connect_file net/socket.c:1854 [inline]
 __sys_connect+0x247/0x290 net/socket.c:1871
 __do_sys_connect net/socket.c:1882 [inline]
 __se_sys_connect net/socket.c:1879 [inline]
 __x64_sys_connect+0x3d/0x50 net/socket.c:1879
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a0b97a30 of 4 bytes by task 22147 on cpu 0:
 unix_dgram_poll+0x6e/0x3b0 net/unix/af_unix.c:2701
 sock_poll+0x185/0x1a0 net/socket.c:1266
 vfs_poll include/linux/poll.h:90 [inline]
 ep_item_poll fs/eventpoll.c:887 [inline]
 ep_send_events_proc+0x246/0x620 fs/eventpoll.c:1744
 ep_scan_ready_list+0x13e/0x330 fs/eventpoll.c:714
 ep_send_events fs/eventpoll.c:1788 [inline]
 ep_poll fs/eventpoll.c:1944 [inline]
 do_epoll_wait+0x4d3/0x870 fs/eventpoll.c:2333
 __do_sys_epoll_wait fs/eventpoll.c:2343 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2340 [inline]
 __x64_sys_epoll_wait+0x4d/0x60 fs/eventpoll.c:2340
 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: 22147 Comm: syz-executor.1 Not tainted 5.8.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (5):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report
ci2-upstream-kcsan-gce	2020/07/23 17:47	upstream	d15be546031c	70c104a1	.config	log	report
ci2-upstream-kcsan-gce	2020/07/09 02:08	upstream	63e1968a2c87	9f9845eb	.config	log	report
ci2-upstream-kcsan-gce	2020/07/06 21:15	upstream	5c82ec00dd00	ef278c73	.config	log	report
ci2-upstream-kcsan-gce	2020/06/27 09:16	upstream	1590a2e1c681	032b4239	.config	log	report
ci2-upstream-kcsan-gce	2020/06/23 20:28	upstream	3e08a95294a4	6930bbef	.config	log	report