KCSAN: data-race in do_epoll_wait / ep_done

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_epoll_wait / ep_done_scan fs	6				6	1748d	1802d	0/29	auto-closed as invalid on 2021/04/16 23:06
upstream	KCSAN: data-race in do_epoll_wait / ep_done_scan (3) fs	6				1	1526d	1526d	0/29	auto-closed as invalid on 2021/11/25 09:53

================================================================== BUG: KCSAN: data-race in do_epoll_wait / ep_done_scan write to 0xffff8881027071d8 of 8 bytes by task 1767 on cpu 1: __list_add include/linux/list.h:70 [inline] list_add include/linux/list.h:86 [inline] ep_done_scan+0xab/0x270 fs/eventpoll.c:644 ep_send_events fs/eventpoll.c:1715 [inline] ep_poll fs/eventpoll.c:1798 [inline] do_epoll_wait+0x91c/0xf00 fs/eventpoll.c:2226 do_epoll_pwait fs/eventpoll.c:2260 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2273 [inline] __se_sys_epoll_pwait+0xfb/0x210 fs/eventpoll.c:2267 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2267 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881027071d8 of 8 bytes by task 1754 on cpu 0: list_empty_careful include/linux/list.h:319 [inline] ep_events_available fs/eventpoll.c:374 [inline] ep_poll fs/eventpoll.c:1789 [inline] do_epoll_wait+0x292/0xf00 fs/eventpoll.c:2226 do_epoll_pwait fs/eventpoll.c:2260 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2273 [inline] __se_sys_epoll_pwait+0xfb/0x210 fs/eventpoll.c:2267 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2267 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1754 Comm: syz-fuzzer Not tainted 5.13.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================