CVE-2026-89644

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> btrfs: fix extent map leak in NOCOW direct I/O write<br /> <br /> btrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an<br /> extent map reference that must be dropped on all exit paths.<br /> <br /> For direct writes into a NOCOW range, btrfs_get_blocks_direct_write()<br /> keeps using that extent map and asks btrfs_create_dio_extent() to<br /> allocate the ordered extent. If that fails, for example because<br /> btrfs_alloc_ordered_extent() fails, the function returns the error<br /> without dropping the input extent map. The PREALLOC path avoided this by<br /> dropping the input extent map before replacing it with the newly created<br /> one.<br /> <br /> Check the error from btrfs_create_dio_extent() before replacing the<br /> map and drop the input extent map on failure.