KCSAN: data-race in fasync_remove_entry / sock_wake

KCSAN: data-race in fasync_remove_entry / sock_wake_async (4)
Status: auto-closed as invalid on 2020/09/26 10:37
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 422d, last: 422d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in fasync_remove_entry / sock_wake_async	1	580d	580d	0/22	auto-closed as invalid on 2020/05/26 22:23
upstream	KCSAN: data-race in fasync_remove_entry / sock_wake_async (5)	3	149d	186d	0/22	auto-closed as invalid on 2021/06/26 18:07
upstream	KCSAN: data-race in fasync_remove_entry / sock_wake_async (2)	1	506d	506d	0/22	closed as invalid on 2020/06/18 14:13
upstream	KCSAN: data-race in fasync_remove_entry / sock_wake_async (3)	1	474d	474d	0/22	auto-closed as invalid on 2020/08/05 10:16

Sample crash report:

==================================================================
BUG: KCSAN: data-race in fasync_remove_entry / sock_wake_async

write to 0xffff88812553a658 of 8 bytes by task 26815 on cpu 0:
 fasync_remove_entry+0xd5/0x140 fs/fcntl.c:884
 fasync_helper+0x92/0xc0 fs/fcntl.c:983
 sock_fasync+0x5c/0xc0 net/socket.c:1302
 __fput+0x48c/0x4d0 fs/file_table.c:278
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:139 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:241
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812553a658 of 8 bytes by task 26809 on cpu 1:
 sock_wake_async+0x26/0x100 net/socket.c:1317
 sk_wake_async include/net/sock.h:2261 [inline]
 unix_release_sock+0x330/0x650 net/unix/af_unix.c:553
 unix_release+0x2f/0x50 net/unix/af_unix.c:861
 __sock_release net/socket.c:596 [inline]
 sock_close+0x6c/0x150 net/socket.c:1277
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:139 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:241
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26809 Comm: syz-executor.3 Not tainted 5.9.0-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	2020/08/22 10:30	upstream	f873db9acd3c	6436ce4b	.config	log	report