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

btrfs: remove BUG() after failure to insert delayed dir index item

Instead of calling BUG() when we fail to insert a delayed dir index item
into the delayed node's tree, we can just release all the resources we
have allocated/acquired before and return the error to the caller. This is
fine because all existing call chains undo anything they have done before
calling btrfs_insert_delayed_dir_index() or BUG_ON (when creating pending
snapshots in the transaction commit path).

So remove the BUG() call and do proper error handling.

This relates to a syzbot report linked below, but does not fix it because
it only prevents hitting a BUG(), it does not fix the issue where somehow
we attempt to use twice the same index number for different index items.

Linux https://git.kernel.org/stable/c/2c58c3931ede7cd08cbecf1f1a4acaf0a04a41a9 [No types assigned]

Linux https://git.kernel.org/stable/c/39c4a9522db0072570d602e9b365119e17fb9f4f [No types assigned]

Linux https://git.kernel.org/stable/c/d10fd53393cc5de4b9cf1a4b8f9984f0a037aa51 [No types assigned]