In the Linux kernel, the following vulnerability has been resolved:

ext4: avoid allocating blocks from corrupted group in ext4_mb_try_best_found()

Determine if the group block bitmap is corrupted before using ac_b_ex in
ext4_mb_try_best_found() to avoid allocating blocks from a group with a
corrupted block bitmap in the following concurrency and making the
situation worse.

ext4_mb_regular_allocator
  ext4_lock_group(sb, group)
  ext4_mb_good_group
   // check if the group bbitmap is corrupted
  ext4_mb_complex_scan_group
   // Scan group gets ac_b_ex but doesn't use it
  ext4_unlock_group(sb, group)
                           ext4_mark_group_bitmap_corrupted(group)
                           // The block bitmap was corrupted during
                           // the group unlock gap.
  ext4_mb_try_best_found
    ext4_lock_group(ac->ac_sb, group)
    ext4_mb_use_best_found
      mb_mark_used
      // Allocating blocks in block bitmap corrupted group

kernel.org https://git.kernel.org/stable/c/0184747b552d6b5a14db3b7fcc3b792ce64dedd1 [No types assigned]

kernel.org https://git.kernel.org/stable/c/21f8cfe79f776287459343e9cfa6055af61328ea [No types assigned]

kernel.org https://git.kernel.org/stable/c/260fc96283c0f594de18a1b045faf6d8fb42874d [No types assigned]

kernel.org https://git.kernel.org/stable/c/4530b3660d396a646aad91a787b6ab37cf604b53 [No types assigned]

kernel.org https://git.kernel.org/stable/c/4c21fa60a6f4606f6214a38f50612b17b2f738f5 [No types assigned]

kernel.org https://git.kernel.org/stable/c/927794a02169778c9c2e7b25c768ab3ea8c1dc03 [No types assigned]

kernel.org https://git.kernel.org/stable/c/a2576ae9a35c078e488f2c573e9e6821d651fbbe [No types assigned]

kernel.org https://git.kernel.org/stable/c/f97e75fa4e12b0aa0224e83fcbda8853ac2adf36 [No types assigned]