CVE-2024-26775: aoe: avoid potential deadlock at set_capacity

CVE-2024-26775: aoe: avoid potential deadlock at set_capacity

[Greg Kroah-Hartman]

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

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

aoe: avoid potential deadlock at set_capacity

Move set_capacity() outside of the section procected by (&d->lock).
To avoid possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
[1] lock(&bdev->bd_size_lock);
                                local_irq_disable();
                            [2] lock(&d->lock);
                            [3] lock(&bdev->bd_size_lock);
   <Interrupt>
[4]  lock(&d->lock);

  *** DEADLOCK ***

Where [1](&bdev->bd_size_lock) hold by zram_add()->set_capacity().
[2]lock(&d->lock) hold by aoeblk_gdalloc(). And aoeblk_gdalloc()
is trying to acquire [3](&bdev->bd_size_lock) at set_capacity() call.
In this situation an attempt to acquire [4]lock(&d->lock) from
aoecmd_cfg_rsp() will lead to deadlock.

So the simplest solution is breaking lock dependency
[2](&d->lock) -> [3](&bdev->bd_size_lock) by moving set_capacity()
outside.

The Linux kernel CVE team has assigned CVE-2024-26775 to this issue.


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

	Fixed in 6.1.80 with commit 2d623c94fbba
	Fixed in 6.6.19 with commit 673629018ba0
	Fixed in 6.7.7 with commit 19a77b271638
	Fixed in 6.8 with commit e169bd4fb2b3

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-2024-26775
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/block/aoe/aoeblk.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/2d623c94fbba3554f4446ba6f3c764994e8b0d26
	https://git.kernel.org/stable/c/673629018ba04906899dcb631beec34d871f709c
	https://git.kernel.org/stable/c/19a77b27163820f793b4d022979ffdca8f659b77
	https://git.kernel.org/stable/c/e169bd4fb2b36c4b2bee63c35c740c85daeb2e86