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BUG: KCSAN: data-race in __ext4_new_inode / find_next_zero_bit

write to 0xffff888122860010 of 8 bytes by task 8416 on cpu 1:
 __test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:76 [inline]
 __test_and_set_bit_le include/asm-generic/bitops/le.h:90 [inline]
 __ext4_new_inode+0xf39/0x2f10 fs/ext4/ialloc.c:939
 ext4_symlink+0x31c/0x9b0 fs/ext4/namei.c:3275
 vfs_symlink fs/namei.c:4131 [inline]
 vfs_symlink+0x218/0x310 fs/namei.c:4117
 do_symlinkat+0x1a5/0x1e0 fs/namei.c:4158
 __do_sys_symlink fs/namei.c:4177 [inline]
 __se_sys_symlink fs/namei.c:4175 [inline]
 __x64_sys_symlink+0x3f/0x50 fs/namei.c:4175
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888122860010 of 8 bytes by task 8415 on cpu 0:
 _find_next_bit lib/find_bit.c:39 [inline]
 find_next_zero_bit+0x4e/0xe0 lib/find_bit.c:79
 find_next_zero_bit_le include/asm-generic/bitops/le.h:15 [inline]
 find_inode_bit.isra.0+0x82/0x300 fs/ext4/ialloc.c:710
 __ext4_new_inode+0xd45/0x2f10 fs/ext4/ialloc.c:909
 ext4_tmpfile+0x15d/0x310 fs/ext4/namei.c:2660
 vfs_tmpfile+0xd3/0x1f0 fs/namei.c:3455
 ovl_do_tmpfile fs/overlayfs/overlayfs.h:188 [inline]
 ovl_make_workdir fs/overlayfs/super.c:1114 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1191 [inline]
 ovl_fill_super+0xcce/0x2736 fs/overlayfs/super.c:1611
 mount_nodev+0x6b/0xf0 fs/super.c:1461
 ovl_mount+0x36/0x50 fs/overlayfs/super.c:1712
 legacy_get_tree+0x7e/0xf0 fs/fs_context.c:647
 vfs_get_tree+0x56/0x1a0 fs/super.c:1545
 do_new_mount fs/namespace.c:2822 [inline]
 do_mount+0x1004/0x14f0 fs/namespace.c:3142
 ksys_mount+0xe8/0x160 fs/namespace.c:3351
 __do_sys_mount fs/namespace.c:3365 [inline]
 __se_sys_mount fs/namespace.c:3362 [inline]
 __x64_sys_mount+0x70/0x90 fs/namespace.c:3362
 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: 8415 Comm: syz-executor.0 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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