CVE-2026-53319

/// Technical description

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

blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()

wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from

wbt_alloc() and wbt_init(). However, both are expected failure paths:

- wbt_alloc() can return NULL under memory pressure (-ENOMEM)

- wbt_init() can fail with -EBUSY if wbt is already registered

syzbot triggers this by injecting memory allocation failures during MTD

partition creation via ioctl(BLKPG), causing a spurious warning.

wbt_init_enable_default() is a best-effort initialization called from

blk_register_queue() with a void return type. Failure simply means the

disk operates without writeback throttling, which is harmless.

Replace WARN_ON_ONCE with plain if-checks, consistent with how

wbt_set_lat() in the same file already handles these failures. Add a

pr_warn() for the wbt_init() failure to retain diagnostic information

without triggering a full stack trace.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References