{"id":"CVE-2025-38449","summary":"drm/gem: Acquire references on GEM handles for framebuffers","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/gem: Acquire references on GEM handles for framebuffers\n\nA GEM handle can be released while the GEM buffer object is attached\nto a DRM framebuffer. This leads to the release of the dma-buf backing\nthe buffer object, if any. [1] Trying to use the framebuffer in further\nmode-setting operations leads to a segmentation fault. Most easily\nhappens with driver that use shadow planes for vmap-ing the dma-buf\nduring a page flip. An example is shown below.\n\n[  156.791968] ------------[ cut here ]------------\n[  156.796830] WARNING: CPU: 2 PID: 2255 at drivers/dma-buf/dma-buf.c:1527 dma_buf_vmap+0x224/0x430\n[...]\n[  156.942028] RIP: 0010:dma_buf_vmap+0x224/0x430\n[  157.043420] Call Trace:\n[  157.045898]  \u003cTASK\u003e\n[  157.048030]  ? show_trace_log_lvl+0x1af/0x2c0\n[  157.052436]  ? show_trace_log_lvl+0x1af/0x2c0\n[  157.056836]  ? show_trace_log_lvl+0x1af/0x2c0\n[  157.061253]  ? drm_gem_shmem_vmap+0x74/0x710\n[  157.065567]  ? dma_buf_vmap+0x224/0x430\n[  157.069446]  ? __warn.cold+0x58/0xe4\n[  157.073061]  ? dma_buf_vmap+0x224/0x430\n[  157.077111]  ? report_bug+0x1dd/0x390\n[  157.080842]  ? handle_bug+0x5e/0xa0\n[  157.084389]  ? exc_invalid_op+0x14/0x50\n[  157.088291]  ? asm_exc_invalid_op+0x16/0x20\n[  157.092548]  ? dma_buf_vmap+0x224/0x430\n[  157.096663]  ? dma_resv_get_singleton+0x6d/0x230\n[  157.101341]  ? __pfx_dma_buf_vmap+0x10/0x10\n[  157.105588]  ? __pfx_dma_resv_get_singleton+0x10/0x10\n[  157.110697]  drm_gem_shmem_vmap+0x74/0x710\n[  157.114866]  drm_gem_vmap+0xa9/0x1b0\n[  157.118763]  drm_gem_vmap_unlocked+0x46/0xa0\n[  157.123086]  drm_gem_fb_vmap+0xab/0x300\n[  157.126979]  drm_atomic_helper_prepare_planes.part.0+0x487/0xb10\n[  157.133032]  ? lockdep_init_map_type+0x19d/0x880\n[  157.137701]  drm_atomic_helper_commit+0x13d/0x2e0\n[  157.142671]  ? drm_atomic_nonblocking_commit+0xa0/0x180\n[  157.147988]  drm_mode_atomic_ioctl+0x766/0xe40\n[...]\n[  157.346424] ---[ end trace 0000000000000000 ]---\n\nAcquiring GEM handles for the framebuffer's GEM buffer objects prevents\nthis from happening. The framebuffer's cleanup later puts the handle\nreferences.\n\nCommit 1a148af06000 (\"drm/gem-shmem: Use dma_buf from GEM object\ninstance\") triggers the segmentation fault easily by using the dma-buf\nfield more widely. The underlying issue with reference counting has\nbeen present before.\n\nv2:\n- acquire the handle instead of the BO (Christian)\n- fix comment style (Christian)\n- drop the Fixes tag (Christian)\n- rename err_ gotos\n- add missing Link tag","modified":"2026-04-16T04:38:01.608203937Z","published":"2025-07-25T15:27:30.702Z","related":["ALSA-2025:15447","ALSA-2025:15661","ALSA-2025:15785","ALSA-2025:15786","SUSE-SU-2025:02853-1","SUSE-SU-2025:02923-1","SUSE-SU-2025:02969-1","SUSE-SU-2025:02996-1","SUSE-SU-2025:02997-1","SUSE-SU-2025:03011-1","SUSE-SU-2025:03023-1","SUSE-SU-2025:03204-1","SUSE-SU-2025:20577-1","SUSE-SU-2025:20586-1","SUSE-SU-2025:20601-1","SUSE-SU-2025:20602-1","SUSE-SU-2025:21074-1","SUSE-SU-2025:21139-1","SUSE-SU-2025:21179-1","openSUSE-SU-2025:20081-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38449.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/08480e285c6a82ce689008d643e4a51db0aaef8b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3cf520d9860d4ec9f7f32068825da31f18dd3f25"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5307dce878d4126e1b375587318955bd019c3741"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cb4c956a15f8b7f870649454771fc3761f504b5f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38449.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38449"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"319c933c71f3dbdb2b3274d1634d3494c70efa06"},{"fixed":"cb4c956a15f8b7f870649454771fc3761f504b5f"},{"fixed":"08480e285c6a82ce689008d643e4a51db0aaef8b"},{"fixed":"3cf520d9860d4ec9f7f32068825da31f18dd3f25"},{"fixed":"5307dce878d4126e1b375587318955bd019c3741"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38449.json"}}],"schema_version":"1.7.5"}