syzbot

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BUG: KCSAN: data-race in __ext4_new_inode / _find_next_bit

read-write to 0xffff888237c68098 of 8 bytes by task 26387 on cpu 1:
 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_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+0xf4f/0x2fc0 fs/ext4/ialloc.c:1097
 ext4_symlink+0x2cc/0x700 fs/ext4/namei.c:3293
 vfs_symlink+0x241/0x330 fs/namei.c:4248
 do_symlinkat+0x104/0x380 fs/namei.c:4277
 __do_sys_symlink fs/namei.c:4299 [inline]
 __se_sys_symlink fs/namei.c:4297 [inline]
 __x64_sys_symlink+0x52/0x60 fs/namei.c:4297
 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 0xffff888237c68098 of 8 bytes by task 26388 on cpu 0:
 _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_symlink+0x2cc/0x700 fs/ext4/namei.c:3293
 vfs_symlink+0x241/0x330 fs/namei.c:4248
 do_symlinkat+0x104/0x380 fs/namei.c:4277
 __do_sys_symlink fs/namei.c:4299 [inline]
 __se_sys_symlink fs/namei.c:4297 [inline]
 __x64_sys_symlink+0x52/0x60 fs/namei.c:4297
 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: 0x0000000000000000 -> 0x0000000000000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26388 Comm: syz-executor.1 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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