Homepage

Expired Pointer Dereference The advisory has been revoked - it doesn't affect any version of package perf  (opens in a new tab)

Threat Intelligence

EPSS
0.12% (3rd percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-CENTOS6-PERF-16408870
  • published4 May 2026
  • disclosed1 May 2026
Report a new vulnerability Found a mistake?

Introduced: 1 May 2026

CVE-2026-31703  (opens in a new tab)
CWE-825  (opens in a new tab)

Amendment

The Centos security team deemed this advisory irrelevant for Centos:6.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by Centos.

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

writeback: Fix use after free in inode_switch_wbs_work_fn()

inode_switch_wbs_work_fn() has a loop like:

wb_get(new_wb); while (1) { list = llist_del_all(&new_wb->switch_wbs_ctxs); /* Nothing to do? */ if (!list) break; ... process the items ... }

Now adding of items to the list looks like:

wb_queue_isw() if (llist_add(&isw->list, &wb->switch_wbs_ctxs)) queue_work(isw_wq, &wb->switch_work);

Because inode_switch_wbs_work_fn() loops when processing isw items, it can happen that wb->switch_work is pending while wb->switch_wbs_ctxs is empty. This is a problem because in that case wb can get freed (no isw items -> no wb reference) while the work is still pending causing use-after-free issues.

We cannot just fix this by cancelling work when freeing wb because that could still trigger problematic 0 -> 1 transitions on wb refcount due to wb_get() in inode_switch_wbs_work_fn(). It could be all handled with more careful code but that seems unnecessarily complex so let's avoid that until it is proven that the looping actually brings practical benefit. Just remove the loop from inode_switch_wbs_work_fn() instead. That way when wb_queue_isw() queues work, we are guaranteed we have added the first item to wb->switch_wbs_ctxs and nobody is going to remove it (and drop the wb reference it holds) until the queued work runs.