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BUG: KCSAN: data-race in alloc_empty_file / percpu_counter_add_batch

write to 0xffffffff85c08548 of 8 bytes by task 6938 on cpu 1:
 percpu_counter_add_batch+0xca/0x150 lib/percpu_counter.c:91
 percpu_counter_add include/linux/percpu_counter.h:55 [inline]
 percpu_counter_dec include/linux/percpu_counter.h:184 [inline]
 file_free fs/file_table.c:57 [inline]
 __fput+0x35d/0x520 fs/file_table.c:298
 ____fput+0x1f/0x30 fs/file_table.c:313
 task_work_run+0xf6/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x384/0x3a0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff85c08548 of 8 bytes by task 6529 on cpu 0:
 get_nr_files fs/file_table.c:66 [inline]
 alloc_empty_file+0x2d/0x180 fs/file_table.c:142
 alloc_file+0x4e/0x2b0 fs/file_table.c:193
 alloc_file_clone+0x2f/0xa0 fs/file_table.c:244
 create_pipe_files+0x28a/0x3b0 fs/pipe.c:878
 __do_pipe_flags+0x51/0x180 fs/pipe.c:900
 do_pipe2+0x3f/0x150 fs/pipe.c:948
 __do_sys_pipe2 fs/pipe.c:966 [inline]
 __se_sys_pipe2 fs/pipe.c:964 [inline]
 __x64_sys_pipe2+0x3a/0x50 fs/pipe.c:964
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6529 Comm: udevd Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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