Withdrawn by the publisher.

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.

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.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 109 more

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.

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um Sicherheitsmaßnahmen zu umgehen, einen Denial of Service zu verursachen und potentiell Code auszuführen.