iommufd: Take dma_resv lock before dma_buf_unpin() in release path

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80633
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 08:16:48 UTC
Updated2026-08-28 08:16:48 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: iommufd: Take dma_resv lock before dma_buf_unpin() in release path dma_buf_unpin() requires the caller to hold the exporter's dma_resv lock: void dma_buf_unpin(struct dma_buf_attachment *attach) { ... dma_resv_assert_held(dmabuf->resv); ... } iopt_release_pages() calls dma_buf_unpin() without taking that lock, so every iommufd_ioas_destroy()/iommufd_ioas_unmap() that releases the last reference on a DMABUF-backed iopt_pages triggers a WARN. This was hit while running tools/testing/selftests/iommu/iommufd: WARNING: drivers/dma-buf/dma-buf.c:1137 at dma_buf_unpin+0x62/0x70 RIP: 0010:dma_buf_unpin+0x62/0x70 Call Trace: <TASK> dma_buf_unpin+0x62/0x70 iopt_release_pages+0xe4/0x190 iopt_unmap_iova_range+0x1c7/0x290 iopt_unmap_all+0x1a/0x30 iommufd_ioas_destroy+0x1d/0x50 iommufd_fops_release+0x93/0x150 __fput+0xfc/0x2c0 __x64_sys_close+0x3d/0x80 do_syscall_64+0x65/0x180 </TASK> Take the dma_resv lock around dma_buf_unpin() in iopt_release_pages(), matching the iopt_map_dmabuf() convention. dma_buf_detach() acquires the reservation lock internally, so it must remain outside the locked region.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 8c5f9645c3893f0db679d9affe4fe4e665b990dd cc69d0332421fd2943b66dbe5e597bf4fd5af126 git Not specified
CNA Linux Linux affected 8c5f9645c3893f0db679d9affe4fe4e665b990dd e745cd2c749e557c14a15ac931761c3f58c24489 git Not specified
CNA Linux Linux affected 7.1 Not specified
CNA Linux Linux unaffected 7.1 semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/cc69d0332421fd2943b66dbe5e597bf4fd5af126 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e745cd2c749e557c14a15ac931761c3f58c24489 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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