syzbot

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BUG: KCSAN: data-race in timerfd_clock_was_set / timerfd_release

write to 0xffff88814f6549d4 of 1 bytes by task 1 on cpu 0:
 __timerfd_remove_cancel fs/timerfd.c:121 [inline]
 timerfd_remove_cancel fs/timerfd.c:131 [inline]
 timerfd_release+0x5d/0x1c0 fs/timerfd.c:223
 __fput+0x25b/0x4e0 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88814f6549d4 of 1 bytes by task 2414 on cpu 1:
 timerfd_clock_was_set+0x49/0x140 fs/timerfd.c:105
 clock_was_set+0x26/0x30 kernel/time/hrtimer.c:891
 do_adjtimex+0x508/0x670 kernel/time/timekeeping.c:2439
 posix_clock_realtime_adj+0x11/0x20 kernel/time/posix-timers.c:191
 do_clock_adjtime kernel/time/posix-timers.c:1109 [inline]
 __do_sys_clock_adjtime kernel/time/posix-timers.c:1121 [inline]
 __se_sys_clock_adjtime kernel/time/posix-timers.c:1112 [inline]
 __x64_sys_clock_adjtime+0x12c/0x1b0 kernel/time/posix-timers.c:1112
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2414 Comm: syz-executor.3 Not tainted 5.13.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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