{"id":"CVE-2026-80633","summary":"iommufd: Take dma_resv lock before dma_buf_unpin() in release path","details":"In the Linux kernel, the following vulnerability has been resolved:\n\niommufd: Take dma_resv lock before dma_buf_unpin() in release path\n\ndma_buf_unpin() requires the caller to hold the exporter's dma_resv\nlock:\n\n  void dma_buf_unpin(struct dma_buf_attachment *attach)\n  {\n          ...\n          dma_resv_assert_held(dmabuf-\u003eresv);\n          ...\n  }\n\niopt_release_pages() calls dma_buf_unpin() without taking that lock,\nso every iommufd_ioas_destroy()/iommufd_ioas_unmap() that releases\nthe last reference on a DMABUF-backed iopt_pages triggers a WARN.\nThis was hit while running tools/testing/selftests/iommu/iommufd:\n\n  WARNING: drivers/dma-buf/dma-buf.c:1137 at dma_buf_unpin+0x62/0x70\n  RIP: 0010:dma_buf_unpin+0x62/0x70\n  Call Trace:\n   \u003cTASK\u003e\n   dma_buf_unpin+0x62/0x70\n   iopt_release_pages+0xe4/0x190\n   iopt_unmap_iova_range+0x1c7/0x290\n   iopt_unmap_all+0x1a/0x30\n   iommufd_ioas_destroy+0x1d/0x50\n   iommufd_fops_release+0x93/0x150\n   __fput+0xfc/0x2c0\n   __x64_sys_close+0x3d/0x80\n   do_syscall_64+0x65/0x180\n   \u003c/TASK\u003e\n\nTake the dma_resv lock around dma_buf_unpin() in iopt_release_pages(),\nmatching the iopt_map_dmabuf() convention. dma_buf_detach() acquires the\nreservation lock internally, so it must remain outside the locked region.","modified":"2026-08-29T03:47:16.924931476Z","published":"2026-08-28T06:48:48.372Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80633.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cc69d0332421fd2943b66dbe5e597bf4fd5af126"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e745cd2c749e557c14a15ac931761c3f58c24489"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80633.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80633"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8c5f9645c3893f0db679d9affe4fe4e665b990dd"},{"fixed":"cc69d0332421fd2943b66dbe5e597bf4fd5af126"},{"fixed":"e745cd2c749e557c14a15ac931761c3f58c24489"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80633.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.1.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80633.json"}}],"schema_version":"1.9.0"}