KCSAN: data-race in packet_do_bind / packet

KCSAN: data-race in packet_do_bind / packet_sendmsg
Status: auto-closed as invalid on 2020/03/29 00:30
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 612d, last: 612d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in packet_do_bind / packet_sendmsg (3)				1	110d	106d	21/22	internal: reported on 2021/06/07 12:42
upstream	KCSAN: data-race in packet_do_bind / packet_sendmsg (2)				2	406d	412d	0/22	auto-closed as invalid on 2020/09/15 15:20

Sample crash report:

==================================================================
BUG: KCSAN: data-race in packet_do_bind / packet_sendmsg

read to 0xffff8880b0a37cc8 of 2 bytes by task 14066 on cpu 0:
 packet_snd net/packet/af_packet.c:2849 [inline]
 packet_sendmsg+0x134d/0x3b60 net/packet/af_packet.c:2990
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 __sys_sendto+0x21f/0x320 net/socket.c:1985
 __do_sys_sendto net/socket.c:1997 [inline]
 __se_sys_sendto net/socket.c:1993 [inline]
 __x64_sys_sendto+0x89/0xb0 net/socket.c:1993
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880b0a37cc8 of 2 bytes by task 14052 on cpu 1:
 packet_do_bind+0x4c6/0x630 net/packet/af_packet.c:3131
 packet_bind+0xab/0xf0 net/packet/af_packet.c:3205
 __sys_bind+0x1df/0x220 net/socket.c:1649
 __do_sys_bind net/socket.c:1660 [inline]
 __se_sys_bind net/socket.c:1658 [inline]
 __x64_sys_bind+0x4c/0x60 net/socket.c:1658
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14052 Comm: syz-executor.1 Not tainted 5.5.0-rc1-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	2020/01/19 00:24	https://github.com/google/ktsan.git kcsan	245a43005292	bc8bc756	.config	log	report