CVE-2022-50293: btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range

Vulnerability summary

CVE-2022-50293 is a medium (CVSS 5.5) Reachable Assertion vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5% of scored vulnerabilities.

Timeline

1. 15-09-2025
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range If we get -ENOMEM while dropping file extent items in a given range, at btrfs_drop_extents(), due to failure to allocate memory when attempting to increment the reference count for an extent or drop the reference count, we handle it with a BUG_ON(). This is excessive, instead we can simply abort the transaction and return the error to the caller. In fact most callers of btrfs_drop_extents(), directly or indirectly, already abort the transaction if btrfs_drop_extents() returns any error. Also, we already have error paths at btrfs_drop_extents() that may return -ENOMEM and in those cases we abort the transaction, like for example anything that changes the b+tree may return -ENOMEM due to a failure to allocate a new extent buffer when COWing an existing extent buffer, such as a call to btrfs_duplicate_item() for example. So replace the BUG_ON() calls with proper logic to abort the transaction and return the error.

• CWE-617Reachable AssertionThe product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.