In the Linux kernel, the following vulnerability has been resolved: dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning When… (CVE-2026-64590)
A vulnerability in the Linux kernel's dma-buf udmabuf component caused a spurious cacheline overlap warning when CONFIG_DMA_API_DEBUG_SG was enabled. This warning was triggered by redundant CPU cache synchronization during DMA mapping, which is unnecessary and leads to a misleading EEXIST warning about overlapping mappings. The issue was resolved by skipping the redundant CPU sync in udmabuf, aligning its behavior with other dma-buf exporters and preventing the warning.
AI Analysis
Technical Summary
The Linux kernel dma-buf udmabuf driver triggered a spurious cacheline tracking EEXIST warning when CONFIG_DMA_API_DEBUG_SG was enabled. This occurred because udmabuf performed redundant CPU cache synchronization during DMA mapping, causing the DMA debug infrastructure to detect overlapping cacheline mappings. The fix involved passing the DMA_ATTR_SKIP_CPU_SYNC flag to dma_map_sgtable() and dma_unmap_sgtable() in udmabuf, suppressing the redundant sync and the warning. This change aligns udmabuf with other dma-buf exporters that already use this flag and rely on explicit cache synchronization elsewhere.
Potential Impact
The vulnerability causes a misleading kernel warning about overlapping DMA cacheline mappings, which could confuse developers or system administrators monitoring kernel logs. There is no indication of a security breach, data corruption, or system compromise. The issue is primarily a correctness and noise reduction fix in kernel debug output.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to pass the DMA_ATTR_SKIP_CPU_SYNC flag in udmabuf's dma_map_sgtable() and dma_unmap_sgtable() calls, suppressing the redundant CPU sync and the spurious warning. Users should update to a kernel version including this fix. No other mitigation is required.
In the Linux kernel, the following vulnerability has been resolved: dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning When… (CVE-2026-64590)
Description
A vulnerability in the Linux kernel's dma-buf udmabuf component caused a spurious cacheline overlap warning when CONFIG_DMA_API_DEBUG_SG was enabled. This warning was triggered by redundant CPU cache synchronization during DMA mapping, which is unnecessary and leads to a misleading EEXIST warning about overlapping mappings. The issue was resolved by skipping the redundant CPU sync in udmabuf, aligning its behavior with other dma-buf exporters and preventing the warning.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel dma-buf udmabuf driver triggered a spurious cacheline tracking EEXIST warning when CONFIG_DMA_API_DEBUG_SG was enabled. This occurred because udmabuf performed redundant CPU cache synchronization during DMA mapping, causing the DMA debug infrastructure to detect overlapping cacheline mappings. The fix involved passing the DMA_ATTR_SKIP_CPU_SYNC flag to dma_map_sgtable() and dma_unmap_sgtable() in udmabuf, suppressing the redundant sync and the warning. This change aligns udmabuf with other dma-buf exporters that already use this flag and rely on explicit cache synchronization elsewhere.
Potential Impact
The vulnerability causes a misleading kernel warning about overlapping DMA cacheline mappings, which could confuse developers or system administrators monitoring kernel logs. There is no indication of a security breach, data corruption, or system compromise. The issue is primarily a correctness and noise reduction fix in kernel debug output.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to pass the DMA_ATTR_SKIP_CPU_SYNC flag in udmabuf's dma_map_sgtable() and dma_unmap_sgtable() calls, suppressing the redundant CPU sync and the spurious warning. Users should update to a kernel version including this fix. No other mitigation is required.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-j99r-j84h-cmw8
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-64590"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a74cf9fbf8831d5391b057b
Added to database: 08/06/2026, 18:17:03 UTC
Last enriched: 08/06/2026, 19:11:21 UTC
Last updated: 08/07/2026, 00:41:15 UTC
Views: 6
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