This is a note to let you know that I've just added the patch titled
drm/amdgpu: fix zero-size GDS range init on RDNA4
to the 6.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amdgpu-fix-zero-size-gds-range-init-on-rdna4.patch
and it can be found in the queue-6.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 095a8b0ad3c3b5cdc3850d961adb8a8f735220bb Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <[email protected]>
Date: Mon, 20 Apr 2026 14:57:15 -0700
Subject: drm/amdgpu: fix zero-size GDS range init on RDNA4
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Arjan van de Ven <[email protected]>
commit 095a8b0ad3c3b5cdc3850d961adb8a8f735220bb 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/[email protected]%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 <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "Christian König" <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit 5719ce5865279cad4fd5f01011fe037168503f2d)
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -75,6 +75,9 @@ static int amdgpu_ttm_init_on_chip(struc
unsigned int type,
uint64_t size_in_page)
{
+ if (!size_in_page)
+ return 0;
+
return ttm_range_man_init(&adev->mman.bdev, type,
false, size_in_page);
}
Patches currently in stable-queue which might be from [email protected] are
queue-6.18/drm-amdgpu-fix-zero-size-gds-range-init-on-rdna4.patch
