Subject: CVE-2021-47184: i40e: Fix NULL ptr dereference on VSI filter sync

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

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

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

i40e: Fix NULL ptr dereference on VSI filter sync

Remove the reason of null pointer dereference in sync VSI filters.
Added new I40E_VSI_RELEASING flag to signalize deleting and releasing
of VSI resources to sync this thread with sync filters subtask.
Without this patch it is possible to start update the VSI filter list
after VSI is removed, that's causing a kernel oops.

The Linux kernel CVE team has assigned CVE-2021-47184 to this issue.

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

	Issue introduced in 3.12 with commit 41c445ff0f48 and fixed in 4.14.256 with commit 78f2a9e831f9
	Issue introduced in 3.12 with commit 41c445ff0f48 and fixed in 4.19.218 with commit 87c421ab4a43
	Issue introduced in 3.12 with commit 41c445ff0f48 and fixed in 5.4.162 with commit c30162da9132
	Issue introduced in 3.12 with commit 41c445ff0f48 and fixed in 5.10.82 with commit f866513ead43
	Issue introduced in 3.12 with commit 41c445ff0f48 and fixed in 5.15.5 with commit e91e8427a1e1
	Issue introduced in 3.12 with commit 41c445ff0f48 and fixed in 5.16 with commit 37d9e304acd9

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-2021-47184
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/net/ethernet/intel/i40e/i40e.h
	drivers/net/ethernet/intel/i40e/i40e_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/78f2a9e831f9610e3655a0be5e675e1aa2472089
	https://git.kernel.org/stable/c/87c421ab4a43433cb009fea44bbbc77f46913e1d
	https://git.kernel.org/stable/c/c30162da91327e4cdf7cd03079f096bb3654738c
	https://git.kernel.org/stable/c/f866513ead4370402428ef724b03c3312295c178
	https://git.kernel.org/stable/c/e91e8427a1e1633a0261e3bb0201c836ac5b3890
	https://git.kernel.org/stable/c/37d9e304acd903a445df8208b8a13d707902dea6