Subject: CVE-2024-44957: xen: privcmd: Switch from mutex to spinlock for irqfds

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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

xen: privcmd: Switch from mutex to spinlock for irqfds

irqfd_wakeup() gets EPOLLHUP, when it is called by
eventfd_release() by way of wake_up_poll(&ctx->wqh, EPOLLHUP), which
gets called under spin_lock_irqsave(). We can't use a mutex here as it
will lead to a deadlock.

Fix it by switching over to a spin lock.

The Linux kernel CVE team has assigned CVE-2024-44957 to this issue.

Affected and fixed versions
===========================

	Fixed in 6.6.46 with commit c2775ae4d922
	Fixed in 6.10.5 with commit 49f2a5da6785
	Fixed in 6.11 with commit 1c682593096a

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-44957
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/xen/privcmd.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/c2775ae4d9227729f8ca9ee2a068f62a00d5ea9c
	https://git.kernel.org/stable/c/49f2a5da6785b2dbde93e291cae037662440346e
	https://git.kernel.org/stable/c/1c682593096a487fd9aebc079a307ff7a6d054a3