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BUG: KCSAN: data-race in alloc_empty_file / percpu_counter_add_batch

read to 0xffffffff85a08548 of 8 bytes by task 18343 on cpu 1:
 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_pseudo+0x11c/0x1b0 fs/file_table.c:232
 create_pipe_files+0x22a/0x380 fs/pipe.c:776
 __do_pipe_flags+0x51/0x180 fs/pipe.c:807
 do_pipe2+0x3f/0x150 fs/pipe.c:855
 __do_sys_pipe2 fs/pipe.c:873 [inline]
 __se_sys_pipe2 fs/pipe.c:871 [inline]
 __x64_sys_pipe2+0x3a/0x50 fs/pipe.c:871
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffffffff85a08548 of 8 bytes by task 1942 on cpu 0:
 percpu_counter_add_batch+0xca/0x150 lib/percpu_counter.c:91
 percpu_counter_add include/linux/percpu_counter.h:55 [inline]
 percpu_counter_inc include/linux/percpu_counter.h:179 [inline]
 alloc_empty_file+0xd2/0x180 fs/file_table.c:153
 path_openat+0x74/0x36e0 fs/namei.c:3514
 do_filp_open+0x11e/0x1b0 fs/namei.c:3555
 do_open_execat+0x111/0x3d0 fs/exec.c:857
 open_exec+0x50/0x80 fs/exec.c:889
 load_elf_binary+0x4d4/0x2ec0 fs/binfmt_elf.c:756
 search_binary_handler fs/exec.c:1659 [inline]
 search_binary_handler+0x127/0x420 fs/exec.c:1636
 exec_binprm fs/exec.c:1702 [inline]
 __do_execve_file.isra.0+0xb76/0x11d0 fs/exec.c:1822
 do_execveat_common fs/exec.c:1868 [inline]
 do_execve fs/exec.c:1885 [inline]
 __do_sys_execve fs/exec.c:1961 [inline]
 __se_sys_execve fs/exec.c:1956 [inline]
 __x64_sys_execve+0x62/0x80 fs/exec.c:1956
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1942 Comm: udevd Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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