dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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| Linux | Linux Kernel |
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| Linux | Linux Kernel |
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4724-1 | linux-6.12 new package |
Debian DLA |
DLA-4777-1 | linux security update |
Ubuntu USN |
USN-8726-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8727-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-8728-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8760-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8726-2 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8726-3 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-8800-1 | Linux kernel (NVIDIA BaseOS) vulnerabilities |
Ubuntu USN |
USN-8760-2 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8726-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8728-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8728-3 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-8917-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8918-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8961-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-9024-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-9025-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-9026-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-9029-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-9040-1 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
Ubuntu USN |
USN-9066-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-9091-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
No CVSS v4.0
No CVSS v3.1
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.165% probability within 30 days)
Key SSVC decision points have not yet been added.
| Type | Values Removed | Values Added |
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| Weaknesses | CWE-532 |
| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning When CONFIG_DMA_API_DEBUG_SG is enabled, importing a udmabuf into a DRM driver (e.g. amdgpu for video playback in GNOME Videos / Showtime) triggers a spurious warning: DMA-API: amdgpu 0000:03:00.0: cacheline tracking EEXIST, \ overlapping mappings aren't supported WARNING: kernel/dma/debug.c:619 at add_dma_entry+0x473/0x5f0 The call chain is: amdgpu_cs_ioctl -> amdgpu_ttm_backend_bind -> dma_buf_map_attachment -> [udmabuf] map_udmabuf -> get_sg_table -> dma_map_sgtable(dev, sg, direction, 0) // attrs=0 -> debug_dma_map_sg -> add_dma_entry -> EEXIST This happens because udmabuf builds a per-page scatter-gather list via sg_set_folio(). When begin_cpu_udmabuf() has already created an sg table mapped for the misc device, and an importer such as amdgpu maps the same pages for its own device via map_udmabuf(), the DMA debug infrastructure sees two active mappings whose physical addresses share cacheline boundaries and warns about the overlap. The DMA_ATTR_SKIP_CPU_SYNC flag suppresses this check in add_dma_entry() because it signals that no CPU cache maintenance is performed at map/unmap time, making the cacheline overlap harmless. All other major dma-buf exporters already pass this flag: - drm_gem_map_dma_buf() passes DMA_ATTR_SKIP_CPU_SYNC - amdgpu_dma_buf_map() passes DMA_ATTR_SKIP_CPU_SYNC The CPU sync at map/unmap time is also redundant for udmabuf: begin_cpu_udmabuf() and end_cpu_udmabuf() already perform explicit cache synchronization via dma_sync_sgtable_for_cpu/device() when CPU access is requested through the dma-buf interface. Pass DMA_ATTR_SKIP_CPU_SYNC to dma_map_sgtable() and dma_unmap_sgtable() in udmabuf to suppress the spurious warning and skip the redundant sync. | |
| Title | dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning | |
| First Time appeared |
Linux
Linux linux Kernel |
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| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
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| References |
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