KCSAN: data-race in ep_insert / ep

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ep_insert / ep_poll fs				3	1601d	1633d	0/26	auto-closed as invalid on 2020/02/15 19:26

==================================================================
BUG: KCSAN: data-race in ep_insert / ep_poll

write to 0xffff88812412dd18 of 8 bytes by task 8909 on cpu 1:
 __list_add include/linux/list.h:70 [inline]
 __list_add include/linux/list.h:63 [inline]
 list_add_tail include/linux/list.h:100 [inline]
 ep_insert+0xb7d/0xcf0 fs/eventpoll.c:1571
 do_epoll_ctl+0x72c/0xf90 fs/eventpoll.c:2226
 __do_sys_epoll_ctl fs/eventpoll.c:2278 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2269 [inline]
 __x64_sys_epoll_ctl+0xb4/0x100 fs/eventpoll.c:2269
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812412dd18 of 8 bytes by task 8921 on cpu 0:
 list_empty_careful include/linux/list.h:301 [inline]
 ep_events_available fs/eventpoll.c:379 [inline]
 ep_poll+0x74b/0x910 fs/eventpoll.c:1902
 do_epoll_wait+0x15a/0x180 fs/eventpoll.c:2320
 __do_sys_epoll_pwait fs/eventpoll.c:2351 [inline]
 __se_sys_epoll_pwait fs/eventpoll.c:2337 [inline]
 __x64_sys_epoll_pwait+0xc6/0x170 fs/eventpoll.c:2337
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8921 Comm: syz-fuzzer Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8921 Comm: syz-fuzzer Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x11d/0x187 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0x1a kernel/kcsan/report.c:626
 kcsan_setup_watchpoint+0x3fb/0x440 kernel/kcsan/core.c:519
 list_empty_careful include/linux/list.h:301 [inline]
 ep_events_available fs/eventpoll.c:379 [inline]
 ep_poll+0x74b/0x910 fs/eventpoll.c:1902
 do_epoll_wait+0x15a/0x180 fs/eventpoll.c:2320
 __do_sys_epoll_pwait fs/eventpoll.c:2351 [inline]
 __se_sys_epoll_pwait fs/eventpoll.c:2337 [inline]
 __x64_sys_epoll_pwait+0xc6/0x170 fs/eventpoll.c:2337
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45b300
Code: 0f 05 89 44 24 20 c3 cc cc cc 8b 7c 24 08 48 8b 74 24 10 8b 54 24 18 44 8b 54 24 1c 49 c7 c0 00 00 00 00 b8 19 01 00 00 0f 05 <89> 44 24 20 c3 cc cc cc cc cc cc cc cc cc cc cc 8b 7c 24 08 48 c7
RSP: 002b:000000c420351858 EFLAGS: 00000246 ORIG_RAX: 0000000000000119
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 000000000045b300
RDX: 0000000000000080 RSI: 000000c420351898 RDI: 0000000000000004
RBP: 000000c420351e98 R08: 0000000000000000 R09: 000000c4201c2600
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000040
R13: 0000000000000040 R14: 0000000000000011 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Time	Kernel	Commit	Syzkaller	Config	Log	Report	Manager
2020/05/10 02:00	https://github.com/google/ktsan.git kcsan	7c3cd68e5d38	8742a2b9	.config	console log	report	ci2-upstream-kcsan-gce
2020/05/05 12:16	https://github.com/google/ktsan.git kcsan	7c3cd68e5d38	4b76dd25	.config	console log	report	ci2-upstream-kcsan-gce
2020/03/18 09:31	https://github.com/google/ktsan.git kcsan	941e0d917bbf	0a96a13c	.config	console log	report	ci2-upstream-kcsan-gce