KCSAN: data-race in sock_alloc_send_pskb / unix_release

KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock (4)
Status: auto-closed as invalid on 2021/02/16 06:00
Reported-by: syzbot+4c2bf55783cf132212f4@syzkaller.appspotmail.com
First crash: 297d, last: 194d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock	2	553d	568d	0/22	auto-closed as invalid on 2020/03/29 01:10
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock (3)	1	357d	357d	0/22	auto-closed as invalid on 2020/09/05 23:08
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock (5)	27	2d15h	45d	21/22	internal: reported on 2021/06/10 14:10
upstream	KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock (2)	1	395d	395d	0/22	auto-closed as invalid on 2020/07/30 12:33

Sample crash report:

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

write to 0xffff88802b46a66a of 1 bytes by task 15603 on cpu 1:
 unix_release_sock+0x25e/0x650 net/unix/af_unix.c:548
 unix_release+0x2f/0x50 net/unix/af_unix.c:859
 __sock_release net/socket.c:597 [inline]
 sock_close+0x6c/0x150 net/socket.c:1256
 __fput+0x24b/0x4e0 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x16b/0x1a0 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88802b46a66a of 1 bytes by task 15609 on cpu 0:
 sock_alloc_send_pskb+0x109/0x4e0 net/core/sock.c:2333
 unix_dgram_sendmsg+0x485/0x1660 net/unix/af_unix.c:1670
 unix_seqpacket_sendmsg+0xc2/0x100 net/unix/af_unix.c:2054
 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: 0 PID: 15609 Comm: syz-executor.0 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (20):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2021/01/12 05:59	upstream	a0d54b4f5b21	2c1f2513	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/31 21:50	upstream	f6e1ea196492	79264ae3	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/26 19:22	upstream	40f78232f973	821e0b09	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/18 08:21	upstream	d64c6f96ba86	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/17 02:20	upstream	5e60366d56c6	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/16 05:23	upstream	d635a69dd498	f213e07e	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/08 02:12	upstream	cd796ed33450	51a9082e	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/29 10:21	upstream	67f34fa8893e	a0092f9d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/28 01:03	upstream	85a2c56cb445	486f93ef	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/16 17:02	upstream	09162bc32c88	1bf9a662	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/15 23:24	upstream	0062442ecfef	1bf9a662	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/10 14:03	upstream	407ab579637c	cca87986	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/09 01:43	upstream	9dbc1c03eeb5	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/08 00:07	upstream	659caaf65dc9	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/06 09:23	upstream	521b619acdc8	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/04 14:50	upstream	4ef8451b3326	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/14 20:15	upstream	b5fc7a89e58b	fc7735a2	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/13 14:05	upstream	865c50e1d279	bd69ee0d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/07 17:44	upstream	c85fb28b6f99	1880b4a9	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/01 12:38	upstream	60e720931556	4103fce0	.config	log	report	info