CVE-2026-72476: dmaengine: Fix possible use after free

CVE-2026-72476: dmaengine: Fix possible use after free

[Greg Kroah-Hartman]

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

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

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

dmaengine: Fix possible use after free

In dma_release_channel(), check chan->device->privatecnt after call
dma_chan_put(). However, dma_chan_put() call dma_device_put() which could
release the last reference of the device if the DMA provider is already
gone and hence free it.

Fixes it by moving dma_chan_put() after the check.

The Linux kernel CVE team has assigned CVE-2026-72476 to this issue.


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

	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 5.10.261 with commit 444f96066937f3fdf0e79b53289cff223c7d638b
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 5.15.212 with commit ab438a9efb9042c79d2f8db28a326d55feb8591f
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 6.1.178 with commit 9bdc8dce4068dadbdf7cf5ad6d4983e2afffedce
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 6.6.145 with commit 5876f38b67a309c00628942cb25679749b53b397
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 6.12.97 with commit 3b0240483dc977dbec4f3bc7a5383d4691ecb625
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 6.18.40 with commit 329ec20a86091d2a6e5b4fe507545e7d678a22a2
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 7.1.5 with commit 0bc191050c3253da8ef4bfaf157c44efed6e22cd
	Issue introduced in 2.6.30 with commit 0f571515c332e00b3515dbe0859ceaa30ab66e00 and fixed in 7.2-rc1 with commit 92f853f0645aebf1d05d333e97ab7c342ace1892

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-2026-72476
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/dma/dmaengine.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/444f96066937f3fdf0e79b53289cff223c7d638b
	https://git.kernel.org/stable/c/ab438a9efb9042c79d2f8db28a326d55feb8591f
	https://git.kernel.org/stable/c/9bdc8dce4068dadbdf7cf5ad6d4983e2afffedce
	https://git.kernel.org/stable/c/5876f38b67a309c00628942cb25679749b53b397
	https://git.kernel.org/stable/c/3b0240483dc977dbec4f3bc7a5383d4691ecb625
	https://git.kernel.org/stable/c/329ec20a86091d2a6e5b4fe507545e7d678a22a2
	https://git.kernel.org/stable/c/0bc191050c3253da8ef4bfaf157c44efed6e22cd
	https://git.kernel.org/stable/c/92f853f0645aebf1d05d333e97ab7c342ace1892