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BUG: KCSAN: data-race in alloc_empty_file / percpu_counter_add_batch

read to 0xffffffff85c08548 of 8 bytes by task 9562 on cpu 0:
 get_nr_files fs/file_table.c:66 [inline]
 alloc_empty_file+0x2d/0x180 fs/file_table.c:142
 path_openat+0x74/0x3580 fs/namei.c:3526
 do_filp_open+0x11e/0x1b0 fs/namei.c:3567
 do_open_execat+0x111/0x3d0 fs/exec.c:856
 open_exec+0x50/0x80 fs/exec.c:888
 load_elf_binary+0x3be/0x2ef0 fs/binfmt_elf.c:759
 search_binary_handler fs/exec.c:1658 [inline]
 search_binary_handler+0x127/0x420 fs/exec.c:1635
 exec_binprm fs/exec.c:1701 [inline]
 __do_execve_file.isra.0+0xb6a/0x1140 fs/exec.c:1821
 do_execveat_common fs/exec.c:1867 [inline]
 do_execve fs/exec.c:1884 [inline]
 __do_sys_execve fs/exec.c:1960 [inline]
 __se_sys_execve fs/exec.c:1955 [inline]
 __x64_sys_execve+0x62/0x80 fs/exec.c:1955
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffffffff85c08548 of 8 bytes by task 7709 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_inc include/linux/percpu_counter.h:179 [inline]
 alloc_empty_file+0xd2/0x180 fs/file_table.c:153
 alloc_file+0x4e/0x2b0 fs/file_table.c:193
 alloc_file_pseudo+0x11c/0x1b0 fs/file_table.c:232
 anon_inode_getfile fs/anon_inodes.c:91 [inline]
 anon_inode_getfile+0x103/0x1d0 fs/anon_inodes.c:74
 do_epoll_create+0x23c/0x320 fs/eventpoll.c:2047
 __do_sys_epoll_create1 fs/eventpoll.c:2066 [inline]
 __se_sys_epoll_create1 fs/eventpoll.c:2064 [inline]
 __x64_sys_epoll_create1+0x28/0x40 fs/eventpoll.c:2064
 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: 1 PID: 7709 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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