syzbot

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BUG: KCSAN: data-race in __ep_remove / __fput

write to 0xffff888103cfb4d0 of 8 bytes by task 18623 on cpu 0:
 __ep_remove+0x3b4/0x430 fs/eventpoll.c:744
 ep_remove_safe fs/eventpoll.c:782 [inline]
 ep_clear_and_put+0x158/0x250 fs/eventpoll.c:818
 ep_eventpoll_release+0x32/0x40 fs/eventpoll.c:834
 __fput+0x245/0x570 fs/file_table.c:321
 ____fput+0x15/0x20 fs/file_table.c:349
 task_work_run+0x135/0x1a0 kernel/task_work.c:179
 get_signal+0xe6a/0xff0 kernel/signal.c:2652
 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888103cfb4d0 of 8 bytes by task 18616 on cpu 1:
 eventpoll_release include/linux/eventpoll.h:45 [inline]
 __fput+0x1c8/0x570 fs/file_table.c:312
 ____fput+0x15/0x20 fs/file_table.c:349
 task_work_run+0x135/0x1a0 kernel/task_work.c:179
 get_signal+0xe6a/0xff0 kernel/signal.c:2652
 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffff888103bc99b0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18616 Comm: syz-executor.2 Not tainted 6.4.0-rc7-syzkaller-00234-g547cc9be86f4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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