CVE-2026-53319

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()<br /> <br /> wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from<br /> wbt_alloc() and wbt_init(). However, both are expected failure paths:<br /> <br /> - wbt_alloc() can return NULL under memory pressure (-ENOMEM)<br /> - wbt_init() can fail with -EBUSY if wbt is already registered<br /> <br /> syzbot triggers this by injecting memory allocation failures during MTD<br /> partition creation via ioctl(BLKPG), causing a spurious warning.<br /> <br /> wbt_init_enable_default() is a best-effort initialization called from<br /> blk_register_queue() with a void return type. Failure simply means the<br /> disk operates without writeback throttling, which is harmless.<br /> <br /> Replace WARN_ON_ONCE with plain if-checks, consistent with how<br /> wbt_set_lat() in the same file already handles these failures. Add a<br /> pr_warn() for the wbt_init() failure to retain diagnostic information<br /> without triggering a full stack trace.