Subject: CVE-2024-26943: nouveau/dmem: handle kcalloc() allocation failure

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

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

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

nouveau/dmem: handle kcalloc() allocation failure

The kcalloc() in nouveau_dmem_evict_chunk() will return null if
the physical memory has run out. As a result, if we dereference
src_pfns, dst_pfns or dma_addrs, the null pointer dereference bugs
will happen.

Moreover, the GPU is going away. If the kcalloc() fails, we could not
evict all pages mapping a chunk. So this patch adds a __GFP_NOFAIL
flag in kcalloc().

Finally, as there is no need to have physically contiguous memory,
this patch switches kcalloc() to kvcalloc() in order to avoid
failing allocations.

The Linux kernel CVE team has assigned CVE-2024-26943 to this issue.

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

	Issue introduced in 6.1 with commit 249881232e14 and fixed in 6.1.84 with commit 9acfd8b083a0
	Issue introduced in 6.1 with commit 249881232e14 and fixed in 6.6.24 with commit 2a84744a037b
	Issue introduced in 6.1 with commit 249881232e14 and fixed in 6.7.12 with commit 5e81773757a9
	Issue introduced in 6.1 with commit 249881232e14 and fixed in 6.8.3 with commit 3e82f7383e0b
	Issue introduced in 6.1 with commit 249881232e14 and fixed in 6.9 with commit 16e87fe23d4a

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-2024-26943
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/nouveau/nouveau_dmem.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/9acfd8b083a0ffbd387566800d89f55058a68af2
	https://git.kernel.org/stable/c/2a84744a037b8a511d6a9055f3defddc28ff4a4d
	https://git.kernel.org/stable/c/5e81773757a95fc298e96cfd6d4700f07b6192a2
	https://git.kernel.org/stable/c/3e82f7383e0b82a835e6b6b06a348b2bc4e2c2ee
	https://git.kernel.org/stable/c/16e87fe23d4af6df920406494ced5c0f4354567b