CVE-2026-74309: vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler

CVE-2026-74309: vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler

Look up the IRQ index in oct_hw->irqs instead of assuming
irq - irqs[0]. This supports non-contiguous IRQ numbers and
avoids incorrect ring indexing when irqs[0] is not the base.

The Linux kernel CVE team has assigned CVE-2026-74309 to this issue.


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

	Issue introduced in 6.14 with commit 26f8ce06af6475b33b0bc60261e9f5027f9af58f and fixed in 6.18.40 with commit 3ef0cfa77a3d526591be069850d186c255e3f0cc
	Issue introduced in 6.14 with commit 26f8ce06af6475b33b0bc60261e9f5027f9af58f and fixed in 7.1.5 with commit c6c7eae5de798442987619434171ac886035d57c
	Issue introduced in 6.14 with commit 26f8ce06af6475b33b0bc60261e9f5027f9af58f and fixed in 7.2-rc1 with commit 0d21a1d6375a05274291e32c1ab7cd57dbb69513

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-2026-74309
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/vdpa/octeon_ep/octep_vdpa_main.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/3ef0cfa77a3d526591be069850d186c255e3f0cc
	https://git.kernel.org/stable/c/c6c7eae5de798442987619434171ac886035d57c
	https://git.kernel.org/stable/c/0d21a1d6375a05274291e32c1ab7cd57dbb69513