CVE-2026-74454: drm/vc4: Supply the overflow slot size in BPOS, not the whole bin BO size

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

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

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

drm/vc4: Supply the overflow slot size in BPOS, not the whole bin BO size

vc4_overflow_mem_work() points BPOA at a 512KB slot inside the 16MB
binner BO, but writes the size of the whole BO to BPOS. On every binner
out-of-memory event the PTB is therefore authorized to write tile lists
across all the other slots (which may hold the tile state, tile alloc and
overflow memory of in-flight jobs) and, for any slot but the first, past
the end of the binner BO into unrelated CMA memory.

Since CMA pages are recycled into page cache and user allocations, this
is arbitrary memory corruption by GPU DMA. In practice it shows up as GPU
hangs with corrupted control list pointers, userspace heap corruption, a
GPU that stays permanently wedged after the first hang, and occasional
full system crashes, whenever a job overflows the initial binner slot.

The bug dates back to the conversion from a dedicated overflow BO (where
writing the full BO size was correct) to the slotted binner BO.

The Linux kernel CVE team has assigned CVE-2026-74454 to this issue.


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

	Issue introduced in 4.13 with commit 553c942f8b2cbc7394b4d4fa2f848b23a8f07451 and fixed in 6.6.151 with commit 2f2291a119e9a8b696ae8bb36e86b75d272ceaea
	Issue introduced in 4.13 with commit 553c942f8b2cbc7394b4d4fa2f848b23a8f07451 and fixed in 6.12.103 with commit 0badb30871004d34df87be33e853536f0b69885f
	Issue introduced in 4.13 with commit 553c942f8b2cbc7394b4d4fa2f848b23a8f07451 and fixed in 6.18.44 with commit 6cd5acf6f87c073622bd61e38fe99c47365cda9c
	Issue introduced in 4.13 with commit 553c942f8b2cbc7394b4d4fa2f848b23a8f07451 and fixed in 7.1.8 with commit 1e33ca7f44be64beed2735bb76b86eb65ba8c05b
	Issue introduced in 4.13 with commit 553c942f8b2cbc7394b4d4fa2f848b23a8f07451 and fixed in 7.2-rc6 with commit 6395789e4739aa5177bbec0fa0f07ccc38d249b0

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-2026-74454
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/gpu/drm/vc4/vc4_irq.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/2f2291a119e9a8b696ae8bb36e86b75d272ceaea
	https://git.kernel.org/stable/c/0badb30871004d34df87be33e853536f0b69885f
	https://git.kernel.org/stable/c/6cd5acf6f87c073622bd61e38fe99c47365cda9c
	https://git.kernel.org/stable/c/1e33ca7f44be64beed2735bb76b86eb65ba8c05b
	https://git.kernel.org/stable/c/6395789e4739aa5177bbec0fa0f07ccc38d249b0