{"id":"AZL-72406","summary":"CVE-2025-38389 affecting package kernel for versions less than 5.15.200.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/i915/gt: Fix timeline left held on VMA alloc error\n\nThe following error has been reported sporadically by CI when a test\nunbinds the i915 driver on a ring submission platform:\n\n\u003c4\u003e [239.330153] ------------[ cut here ]------------\n\u003c4\u003e [239.330166] i915 0000:00:02.0: [drm] drm_WARN_ON(dev_priv-\u003emm.shrink_count)\n\u003c4\u003e [239.330196] WARNING: CPU: 1 PID: 18570 at drivers/gpu/drm/i915/i915_gem.c:1309 i915_gem_cleanup_early+0x13e/0x150 [i915]\n...\n\u003c4\u003e [239.330640] RIP: 0010:i915_gem_cleanup_early+0x13e/0x150 [i915]\n...\n\u003c4\u003e [239.330942] Call Trace:\n\u003c4\u003e [239.330944]  \u003cTASK\u003e\n\u003c4\u003e [239.330949]  i915_driver_late_release+0x2b/0xa0 [i915]\n\u003c4\u003e [239.331202]  i915_driver_release+0x86/0xa0 [i915]\n\u003c4\u003e [239.331482]  devm_drm_dev_init_release+0x61/0x90\n\u003c4\u003e [239.331494]  devm_action_release+0x15/0x30\n\u003c4\u003e [239.331504]  release_nodes+0x3d/0x120\n\u003c4\u003e [239.331517]  devres_release_all+0x96/0xd0\n\u003c4\u003e [239.331533]  device_unbind_cleanup+0x12/0x80\n\u003c4\u003e [239.331543]  device_release_driver_internal+0x23a/0x280\n\u003c4\u003e [239.331550]  ? bus_find_device+0xa5/0xe0\n\u003c4\u003e [239.331563]  device_driver_detach+0x14/0x20\n...\n\u003c4\u003e [357.719679] ---[ end trace 0000000000000000 ]---\n\nIf the test also unloads the i915 module then that's followed with:\n\n\u003c3\u003e [357.787478] =============================================================================\n\u003c3\u003e [357.788006] BUG i915_vma (Tainted: G     U  W        N ): Objects remaining on __kmem_cache_shutdown()\n\u003c3\u003e [357.788031] -----------------------------------------------------------------------------\n\u003c3\u003e [357.788204] Object 0xffff888109e7f480 @offset=29824\n\u003c3\u003e [357.788670] Allocated in i915_vma_instance+0xee/0xc10 [i915] age=292729 cpu=4 pid=2244\n\u003c4\u003e [357.788994]  i915_vma_instance+0xee/0xc10 [i915]\n\u003c4\u003e [357.789290]  init_status_page+0x7b/0x420 [i915]\n\u003c4\u003e [357.789532]  intel_engines_init+0x1d8/0x980 [i915]\n\u003c4\u003e [357.789772]  intel_gt_init+0x175/0x450 [i915]\n\u003c4\u003e [357.790014]  i915_gem_init+0x113/0x340 [i915]\n\u003c4\u003e [357.790281]  i915_driver_probe+0x847/0xed0 [i915]\n\u003c4\u003e [357.790504]  i915_pci_probe+0xe6/0x220 [i915]\n...\n\nCloser analysis of CI results history has revealed a dependency of the\nerror on a few IGT tests, namely:\n- igt@api_intel_allocator@fork-simple-stress-signal,\n- igt@api_intel_allocator@two-level-inception-interruptible,\n- igt@gem_linear_blits@interruptible,\n- igt@prime_mmap_coherency@ioctl-errors,\nwhich invisibly trigger the issue, then exhibited with first driver unbind\nattempt.\n\nAll of the above tests perform actions which are actively interrupted with\nsignals.  Further debugging has allowed to narrow that scope down to\nDRM_IOCTL_I915_GEM_EXECBUFFER2, and ring_context_alloc(), specific to ring\nsubmission, in particular.\n\nIf successful then that function, or its execlists or GuC submission\nequivalent, is supposed to be called only once per GEM context engine,\nfollowed by raise of a flag that prevents the function from being called\nagain.  The function is expected to unwind its internal errors itself, so\nit may be safely called once more after it returns an error.\n\nIn case of ring submission, the function first gets a reference to the\nengine's legacy timeline and then allocates a VMA.  If the VMA allocation\nfails, e.g. when i915_vma_instance() called from inside is interrupted\nwith a signal, then ring_context_alloc() fails, leaving the timeline held\nreferenced.  On next I915_GEM_EXECBUFFER2 IOCTL, another reference to the\ntimeline is got, and only that last one is put on successful completion.\nAs a consequence, the legacy timeline, with its underlying engine status\npage's VMA object, is still held and not released on driver unbind.\n\nGet the legacy timeline only after successful allocation of the context\nengine's VMA.\n\nv2: Add a note on other submission methods (Krzysztof Karas):\n    Both execlists and GuC submission use lrc_alloc() which seems free\n    from a similar issue.\n\n(cherry picked from commit cc43422b3cc79eacff4c5a8ba0d224688ca9dd4f)","modified":"2026-04-01T05:22:34.092879Z","published":"2025-07-25T13:15:28Z","upstream":["CVE-2025-38389"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38389"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.200.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-72406.json"}}],"schema_version":"1.7.5"}