Withdrawn by the publisher.

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

ring-buffer: Stop remote reader update when page swap fails

The remote swap_reader_page callback can return -EBUSY when the writer moves the head before the remote catches it, particularly during an event storm on a small buffer. __rb_get_reader_page_from_remote() currently warns about that failure but continues with the unchanged reader ID and rearranges the local page list as though the swap succeeded.

Handle the callback failure as a recoverable error. Report it with pr_warn_ratelimited() and return NULL. Callers already handle a NULL reader page as a failed attempt. This avoids splicing the same page as both the previous and new reader without flooding the log under contention.

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

ring-buffer: Stop remote reader update when page swap fails

The remote swap_reader_page callback can return -EBUSY when the writer moves the head before the remote catches it, particularly during an event storm on a small buffer. __rb_get_reader_page_from_remote() currently warns about that failure but continues with the unchanged reader ID and rearranges the local page list as though the swap succeeded.

Handle the callback failure as a recoverable error. Report it with pr_warn_ratelimited() and return NULL. Callers already handle a NULL reader page as a failed attempt. This avoids splicing the same page as both the previous and new reader without flooding the log under contention.

kernel-devel-7.2.7-1.1 on GA media

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 96 more

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Stop remote reader update when page swap fails The remote swap_reader_page callback can return -EBUSY when the writer moves the head before the remote catches it, particularly during an event storm on a small buffer. __rb_get_reader_page_from_remote() currently warns about that failure but continues with the unchanged reader ID and rearranges the local page list as though the swap succeeded. Handle the callback failure as a recoverable error. Report it with pr_warn_ratelimited() and return NULL. Callers already handle a NULL reader page as a failed attempt. This avoids splicing the same page as both the previous and new reader without flooding the log under contention.

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um Sicherheitsmaßnahmen zu umgehen, Daten oder den Systemzustand zu manipulieren, Denial-of-Service-Zustände herbeizuführen oder andere, nicht näher spezifizierte Angriffe durchzuführen.