CVE-2026-89644
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix extent map leak in NOCOW direct I/O write btrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an extent map reference that must be dropped on all exit paths. For direct writes into a NOCOW range, btrfs_get_blocks_direct_write() keeps using that extent map and asks btrfs_create_dio_extent() to allocate the ordered extent. If that fails, for example because btrfs_alloc_ordered_extent() fails, the function returns the error without dropping the input extent map. The PREALLOC path avoided this by dropping the input extent map before replacing it with the newly created one. Check the error from btrfs_create_dio_extent() before replacing the map and drop the input extent map on failure.
How to fix
- Linux Linux8d264d35df981e943171ddc09cd6cc1d38c65e17, cb732d302245b14943a5017015fffa8e6db7a6c0, b7c873765875645b11503f94c9bae2ca80127375, f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2, 05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d, 3f950867c307c5413d628a153ac44915bd117ffd or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af ≤ v < 8d264d35df981e943171ddc09cd6cc1d38c65e17, 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af ≤ v < cb732d302245b14943a5017015fffa8e6db7a6c0, 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af ≤ v < b7c873765875645b11503f94c9bae2ca80127375, 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af ≤ v < f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2, 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af ≤ v < 05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d, 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af ≤ v < 3f950867c307c5413d628a153ac44915bd117ffd, 4.7 | 8d264d35df981e943171ddc09cd6cc1d38c65e17, cb732d302245b14943a5017015fffa8e6db7a6c0, b7c873765875645b11503f94c9bae2ca80127375, f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2, 05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d, 3f950867c307c5413d628a153ac44915bd117ffd |
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