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BUG: KCSAN: data-race in __ext4_new_inode / _find_next_bit

write to 0xffff888105b682e8 of 8 bytes by task 13128 on cpu 0:
 instrument_write include/linux/instrumented.h:42 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:79 [inline]
 __test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:95 [inline]
 __test_and_set_bit_le include/asm-generic/bitops/le.h:120 [inline]
 __ext4_new_inode+0xf3e/0x2f70 fs/ext4/ialloc.c:1094
 ext4_symlink+0x2c3/0x700 fs/ext4/namei.c:3465
 vfs_symlink+0x23a/0x300 fs/namei.c:4182
 do_symlinkat+0xeb/0x280 fs/namei.c:4212
 __do_sys_symlink fs/namei.c:4233 [inline]
 __se_sys_symlink fs/namei.c:4231 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4231
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888105b682e8 of 8 bytes by task 13133 on cpu 1:
 _find_next_bit+0x4f/0x190 lib/find_bit.c:41
 find_next_zero_bit include/asm-generic/bitops/find.h:94 [inline]
 find_next_zero_bit_le include/asm-generic/bitops/le.h:17 [inline]
 find_inode_bit+0xc8/0x330 fs/ext4/ialloc.c:723
 __ext4_new_inode+0xc7a/0x2f70 fs/ext4/ialloc.c:1064
 ext4_symlink+0x2c3/0x700 fs/ext4/namei.c:3465
 vfs_symlink+0x23a/0x300 fs/namei.c:4182
 do_symlinkat+0xeb/0x280 fs/namei.c:4212
 __do_sys_symlink fs/namei.c:4233 [inline]
 __se_sys_symlink fs/namei.c:4231 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4231
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000000 -> 0x0000000000000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13133 Comm: syz-executor.0 Tainted: G        W         5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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