CVE-2022-49761: btrfs: always report error in run_one_delayed_ref()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-27 · updated 2026-06-17
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: always report error in run_one_delayed_ref() Currently we have a btrfs_debug() for run_one_delayed_ref() failure, but if end users hit such problem, there will be no chance that btrfs_debug() is enabled. This can lead to very little useful info for debugging. This patch will: - Add extra info for error reporting Including: * logical bytenr * num_bytes * type * action * ref_mod - Replace the btrfs_debug() with btrfs_err() - Move the error reporting into run_one_delayed_ref() This is to avoid use-after-free, the @node can be freed in the caller. This error should only be triggered at most once. As if run_one_delayed_ref() failed, we trigger the error message, then causing the call chain to error out: btrfs_run_delayed_refs() `- btrfs_run_delayed_refs() `- btrfs_run_delayed_refs_for_head() `- run_one_delayed_ref() And we will abort the current transaction in btrfs_run_delayed_refs(). If we have to run delayed refs for the abort transaction, run_one_delayed_ref() will just cleanup the refs and do nothing, thus no new error messages would be output.

Affected products

Linux kernel: before 5.10.165; from 5.11 before 5.15.90; from 5.16 before 6.1.8; 6.2-rc1, 6.2-rc2 — fixed in 5.10.165, 5.15.90, 6.1.8

How to fix

Upgrade to a fixed version: Linux kernel 5.10.165, 5.15.90, 6.1.8. Check the vendor advisory for mitigations.

References

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