Arjan van de Ven 0e21db1a77 drm/amdgpu: fix zero-size GDS range init on RDNA4
commit 095a8b0ad3 upstream.

RDNA4 (GFX 12) hardware removes the GDS, GWS, and OA on-chip memory
resources. The gfx_v12_0 initialisation code correctly leaves
adev->gds.gds_size, adev->gds.gws_size, and adev->gds.oa_size at
zero to reflect this.

amdgpu_ttm_init() unconditionally calls amdgpu_ttm_init_on_chip() for
each of these resources regardless of size. When the size is zero,
amdgpu_ttm_init_on_chip() forwards the call to ttm_range_man_init(),
which calls drm_mm_init(mm, 0, 0). drm_mm_init() immediately fires
DRM_MM_BUG_ON(start + size <= start) -- trivially true when size is
zero -- crashing the kernel during modprobe of amdgpu on an RX 9070 XT.

Guard against this by returning 0 early from
amdgpu_ttm_init_on_chip() when size_in_page is zero. This skips TTM
resource manager registration for hardware resources that are absent,
without affecting any other GPU type.

DRM_MM_BUG_ON() only asserts if CONFIG_DRM_DEBUG_MM is enabled in
the kernel config.  This is apparently rarely enabled as these chips
have been in the market for over a year and this issue was only reported
now.

Link: https://lore.kernel.org/all/bug-221376-2300@https.bugzilla.kernel.org%2F/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221376
Oops-Analysis: http://oops.fenrus.org/reports/bugzilla.korg/221376/report.html
Assisted-by: GitHub Copilot:Claude Sonnet 4.6 linux-kernel-oops-x86.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5719ce5865)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-05-07 06:09:47 +02:00
2025-03-13 13:01:42 +01:00
2024-11-07 14:14:59 -08:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
S
Description
No description provided
Readme 5.5 GiB
Languages
C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%