syzbot

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BUG: KCSAN: data-race in _find_next_bit / ext4_free_inode

read-write to 0xffff888237c69088 of 8 bytes by task 1821 on cpu 0:
 instrument_read_write include/linux/instrumented.h:57 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:81 [inline]
 __test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:109 [inline]
 __test_and_clear_bit_le include/asm-generic/bitops/le.h:125 [inline]
 ext4_free_inode+0x5bf/0xa30 fs/ext4/ialloc.c:316
 ext4_evict_inode+0xbff/0xf10 fs/ext4/inode.c:332
 evict+0x1aa/0x410 fs/inode.c:590
 iput_final fs/inode.c:1670 [inline]
 iput+0x3ef/0x580 fs/inode.c:1696
 dentry_unlink_inode+0x23d/0x250 fs/dcache.c:376
 d_delete+0x78/0xa0 fs/dcache.c:2505
 vfs_rmdir+0x2bf/0x2e0 fs/namei.c:3982
 do_rmdir+0x18d/0x330 fs/namei.c:4030
 __do_sys_rmdir fs/namei.c:4049 [inline]
 __se_sys_rmdir fs/namei.c:4047 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:4047
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c69088 of 8 bytes by task 1816 on cpu 1:
 _find_next_bit+0xe0/0x190 lib/find_bit.c:60
 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:725
 __ext4_new_inode+0xc9a/0x2fc0 fs/ext4/ialloc.c:1066
 ext4_mkdir+0x28a/0x760 fs/ext4/namei.c:2929
 vfs_mkdir+0x2c8/0x3d0 fs/namei.c:3883
 do_mkdirat+0x12e/0x2c0 fs/namei.c:3909
 __do_sys_mkdir fs/namei.c:3929 [inline]
 __se_sys_mkdir fs/namei.c:3927 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:3927
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xbfffffffffffffff -> 0x7fffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1816 Comm: syz-executor.4 Not tainted 5.16.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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