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

write to 0xffff88812183c118 of 8 bytes by task 7830 on cpu 0:
 __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:1549
 do_epoll_ctl+0x72c/0xf90 fs/eventpoll.c:2204
 __do_sys_epoll_ctl fs/eventpoll.c:2256 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2247 [inline]
 __x64_sys_epoll_ctl+0xb4/0x100 fs/eventpoll.c:2247
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812183c118 of 8 bytes by task 7840 on cpu 1:
 list_empty_careful include/linux/list.h:301 [inline]
 ep_events_available fs/eventpoll.c:374 [inline]
 ep_poll+0x74b/0x910 fs/eventpoll.c:1880
 do_epoll_wait+0x15a/0x180 fs/eventpoll.c:2298
 __do_sys_epoll_pwait fs/eventpoll.c:2329 [inline]
 __se_sys_epoll_pwait fs/eventpoll.c:2315 [inline]
 __x64_sys_epoll_pwait+0xc6/0x170 fs/eventpoll.c:2315
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7840 Comm: syz-fuzzer Not tainted 5.6.0-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: 1 PID: 7840 Comm: syz-fuzzer Not tainted 5.6.0-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/0x14 kernel/kcsan/report.c:609
 kcsan_setup_watchpoint+0x3e3/0x420 kernel/kcsan/core.c:503
 list_empty_careful include/linux/list.h:301 [inline]
 ep_events_available fs/eventpoll.c:374 [inline]
 ep_poll+0x74b/0x910 fs/eventpoll.c:1880
 do_epoll_wait+0x15a/0x180 fs/eventpoll.c:2298
 __do_sys_epoll_pwait fs/eventpoll.c:2329 [inline]
 __se_sys_epoll_pwait fs/eventpoll.c:2315 [inline]
 __x64_sys_epoll_pwait+0xc6/0x170 fs/eventpoll.c:2315
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 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:000000c420181860 EFLAGS: 00000246 ORIG_RAX: 0000000000000119
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 000000000045b300
RDX: 0000000000000080 RSI: 000000c4201818a0 RDI: 0000000000000004
RBP: 000000c420181ea0 R08: 0000000000000000 R09: 000000c420001e00
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fdf2b4646c8 R15: 0000000000000001
Kernel Offset: disabled
Rebooting in 86400 seconds..