CVE-2026-43302
Received Received - Intake
DMA API Debug Warning in Linux Kernel V3D Driver

Publication date: 2026-05-08

Last updated on: 2026-05-08

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Set DMA segment size to avoid debug warnings When using V3D rendering with CONFIG_DMA_API_DEBUG enabled, the kernel occasionally reports a segment size mismatch. This is because 'max_seg_size' is not set. The kernel defaults to 64K. setting 'max_seg_size' to the maximum will prevent 'debug_dma_map_sg()' from complaining about the over-mapping of the V3D segment length. DMA-API: v3d 1002000000.v3d: mapping sg segment longer than device claims to support [len=8290304] [max=65536] WARNING: CPU: 0 PID: 493 at kernel/dma/debug.c:1179 debug_dma_map_sg+0x330/0x388 CPU: 0 UID: 0 PID: 493 Comm: Xorg Not tainted 6.12.53-yocto-standard #1 Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT) pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : debug_dma_map_sg+0x330/0x388 lr : debug_dma_map_sg+0x330/0x388 sp : ffff8000829a3ac0 x29: ffff8000829a3ac0 x28: 0000000000000001 x27: ffff8000813fe000 x26: ffffc1ffc0000000 x25: ffff00010fdeb760 x24: 0000000000000000 x23: ffff8000816a9bf0 x22: 0000000000000001 x21: 0000000000000002 x20: 0000000000000002 x19: ffff00010185e810 x18: ffffffffffffffff x17: 69766564206e6168 x16: 74207265676e6f6c x15: 20746e656d676573 x14: 20677320676e6970 x13: 5d34303334393134 x12: 0000000000000000 x11: 00000000000000c0 x10: 00000000000009c0 x9 : ffff8000800e0b7c x8 : ffff00010a315ca0 x7 : ffff8000816a5110 x6 : 0000000000000001 x5 : 000000000000002b x4 : 0000000000000002 x3 : 0000000000000008 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00010a315280 Call trace: debug_dma_map_sg+0x330/0x388 __dma_map_sg_attrs+0xc0/0x278 dma_map_sgtable+0x30/0x58 drm_gem_shmem_get_pages_sgt+0xb4/0x140 v3d_bo_create_finish+0x28/0x130 [v3d] v3d_create_bo_ioctl+0x54/0x180 [v3d] drm_ioctl_kernel+0xc8/0x140 drm_ioctl+0x2d4/0x4d8
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Meta Information
Published
2026-05-08
Last Modified
2026-05-08
Generated
2026-05-09
AI Q&A
2026-05-08
EPSS Evaluated
N/A
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel From 6.12.53 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's V3D rendering component when the CONFIG_DMA_API_DEBUG option is enabled. The issue arises because the 'max_seg_size' parameter, which defines the maximum DMA segment size, is not set. By default, the kernel assumes a maximum segment size of 64K, but the V3D device attempts to map a segment longer than this limit, causing debug warnings about segment size mismatches.

The problem is that the DMA mapping segment length exceeds what the device claims to support, leading to warnings during debug operations. The fix involves setting 'max_seg_size' to the maximum supported value to prevent these debug warnings.


How can this vulnerability impact me? :

This vulnerability primarily causes debug warnings related to DMA segment size mismatches when using V3D rendering with debug DMA API enabled. It does not indicate a security breach or direct functional failure but may lead to confusion or difficulty in debugging kernel operations involving DMA.

There is no indication from the provided information that this vulnerability leads to data corruption, privilege escalation, or denial of service. Its impact is limited to debug message noise and potential developer confusion.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring kernel debug warnings related to DMA segment size mismatches when using V3D rendering with CONFIG_DMA_API_DEBUG enabled.

Specifically, look for kernel log messages indicating a segment size mismatch such as warnings from debug_dma_map_sg about mapping scatter-gather segments longer than the device supports.

You can check the kernel logs for these warnings using commands like:

  • dmesg | grep -i 'debug_dma_map_sg'
  • journalctl -k | grep -i 'debug_dma_map_sg'
  • grep -i 'mapping sg segment longer' /var/log/kern.log

What immediate steps should I take to mitigate this vulnerability?

The vulnerability is resolved by setting the DMA segment size (max_seg_size) to the maximum supported value to avoid debug warnings and segment size mismatches.

Immediate mitigation steps include:

  • Ensure that the Linux kernel is updated to a version where this issue is fixed.
  • If possible, disable CONFIG_DMA_API_DEBUG to prevent debug warnings until the kernel is updated.
  • Review and apply any patches or kernel updates provided by your distribution that address this issue.

How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

The provided information about CVE-2026-43302 does not include any details regarding its impact on compliance with common standards and regulations such as GDPR or HIPAA.


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