CVE-2026-68209: media: sun4i-csi: Return queued buffers on start_streaming() failure

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

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

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

media: sun4i-csi: Return queued buffers on start_streaming() failure

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

sun4i_csi_start_streaming() returned -EINVAL when no matching CSI
format could be found, before any setup (scratch buffer allocation,
pipeline start) had been performed.  The remaining error paths already
converge on the err_clear_dma_queue label, which calls
return_all_buffers(..., VB2_BUF_STATE_QUEUED) under csi->qlock.  Jump
to that label directly: the intermediate err_disable_device /
err_disable_pipeline / err_free_scratch_buffer labels are skipped,
which is correct because nothing they would undo has happened yet.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

The Linux kernel CVE team has assigned CVE-2026-68209 to this issue.


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

	Issue introduced in 5.4 with commit 577bbf23b758848f0c4a50d346460b690c753024 and fixed in 6.6.148 with commit 4872161e6fbe4e1783daea8bff79caddfae0fb82
	Issue introduced in 5.4 with commit 577bbf23b758848f0c4a50d346460b690c753024 and fixed in 6.12.101 with commit a8abecc638a7feb20b78fabd563b05e30c071331
	Issue introduced in 5.4 with commit 577bbf23b758848f0c4a50d346460b690c753024 and fixed in 6.18.42 with commit b5184b3f0e9d4cc47059ba1138c9a73d43d2493f
	Issue introduced in 5.4 with commit 577bbf23b758848f0c4a50d346460b690c753024 and fixed in 7.1.6 with commit 668face37fdb6b6900645dc8777195498541c9a7
	Issue introduced in 5.4 with commit 577bbf23b758848f0c4a50d346460b690c753024 and fixed in 7.2-rc1 with commit bbba3e260a62810a717b4442a3bb96d0ec0f6309

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-2026-68209
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/media/platform/sunxi/sun4i-csi/sun4i_dma.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/4872161e6fbe4e1783daea8bff79caddfae0fb82
	https://git.kernel.org/stable/c/a8abecc638a7feb20b78fabd563b05e30c071331
	https://git.kernel.org/stable/c/b5184b3f0e9d4cc47059ba1138c9a73d43d2493f
	https://git.kernel.org/stable/c/668face37fdb6b6900645dc8777195498541c9a7
	https://git.kernel.org/stable/c/bbba3e260a62810a717b4442a3bb96d0ec0f6309