CVE-2024-41092·Kernel vulnerability
In the Linux kernel, the following vulnerability has been resolved: drm/i915/gt: Fix potential UAF by revoke of fence registers CI has been sporadically reporting the following issue triggered by igt@i915_selftest@live@hangcheck on ADL-P and similar machines: <6> [414.049203] i915: Running intel_hangcheck_live_selftests/igt_reset_evict_fence ... <6> [414.068804] i915 0000:00:02.0: [drm] GT0: GUC: submission enabled <6> [414.068812] i915 0000:00:02.0: [drm] GT0: GUC: SLPC enabled <3> [414.070354] Unable to pin Y-tiled fence; err:-4 <3> [414.071282] i915_vma_revoke_fence:301 GEM_BUG_ON(!i915_active_is_idle(&fence->active)) ... <4>[ 609.603992] ------------[ cut here ]------------ <2>[ 609.603995] kernel BUG at drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c:301! <4>[ 609.604003] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI <4>[ 609.604006] CPU: 0 PID: 268 Comm: kworker/u64:3 Tainted: G U W 6.9.0-CI_DRM_14785-g1ba62f8cea9c+ #1 <4>[ 609.604008] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023 <4>[ 609.604010] Workqueue: i915 __i915_gem_free_work [i915] <4>[ 609.604149] RIP: 0010:i915_vma_revoke_fence+0x187/0x1f0 [i915] ... <4>[ 609.604271] Call Trace: <4>[ 609.604273] <TASK> ... <4>[ 609.604716] __i915_vma_evict+0x2e9/0x550 [i915] <4>[ 609.604852] __i915_vma_unbind+0x7c/0x160 [i915] <4>[ 609.604977] force_unbind+0x24/0xa0 [i915] <4>[ 609.605098] i915_vma_destroy+0x2f/0xa0 [i915] <4>[ 609.605210] __i915_gem_object_pages_fini+0x51/0x2f0 [i915] <4>[ 609.605330] __i915_gem_free_objects.isra.0+0x6a/0xc0 [i915] <4>[ 609.605440] process_scheduled_works+0x351/0x690 ... In the past, there were similar failures reported by CI from other IGT tests, observed on other platforms. Before commit 63baf4f3d587 ("drm/i915/gt: Only wait for GPU activity before unbinding a GGTT fence"), i915_vma_revoke_fence() was waiting for idleness of vma->active via fence_update(). That commit introduced vma->fence->active in order for the fence_update() to be able to wait selectively on that one instead of vma->active since only idleness of fence registers was needed. But then, another commit 0d86ee35097a ("drm/i915/gt: Make fence revocation unequivocal") replaced the call to fence_update() in i915_vma_revoke_fence() with only fence_write(), and also added that GEM_BUG_ON(!i915_active_is_idle(&fence->active)) in front. No justification was provided on why we might then expect idleness of vma->fence->active without first waiting on it. The issue can be potentially caused by a race among revocation of fence registers on one side and sequential execution of signal callbacks invoked on completion of a request that was using them on the other, still processed in parallel to revocation of those fence registers. Fix it by waiting for idleness of vma->fence->active in i915_vma_revoke_fence(). (cherry picked from commit 24bb052d3dd499c5956abad5f7d8e4fd07da7fb1)
- Severity
- high
- Software
- Kernel
- Fixed in
- 6.9.8
- Published
- 2024-07-29
Affected versions
From: 6.7
Until: 6.9.8
Fixed in: 6.9.8
How to fix this CVE
Update your Linux kernel to version 6.9.8 or later to resolve a use-after-free (UAF) vulnerability in the i915 GPU driver's fence register management. The fix ensures proper synchronization when revoking fence registers by waiting for active operations to complete before proceeding. Systems running kernel versions 6.7 through 6.9.7 should prioritize this update to prevent potential system crashes and memory safety issues.
sudo dnf update kernel kernel-develDefensia detects this vulnerability
How to check if you are affected
- Check your current kernel version: uname -r
- Verify if you are running a vulnerable version: if output shows 6.7.x through 6.9.7, your system is affected
- Search kernel logs for fence-related failures: grep -i 'Unable to pin.*fence\|i915_vma_revoke_fence\|GEM_BUG_ON' /var/log/kern.log
- After patching, verify the new kernel version: uname -r (should show 6.9.8 or later)
FAQ
What is CVE-2024-41092?
CVE-2024-41092 is a use-after-free vulnerability in the Linux kernel's i915 Intel GPU driver that occurs during fence register revocation when signal callbacks race with register cleanup operations, potentially causing kernel panics or memory corruption.
Is CVE-2024-41092 being actively exploited?
No, CVE-2024-41092 is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are currently available. However, it can be reliably triggered through specific workload patterns.
What versions of Kernel are affected by CVE-2024-41092?
Linux kernel versions 6.7 through 6.9.7 are vulnerable. The issue was introduced by earlier commits and is fixed in kernel 6.9.8 and all subsequent versions.
How do I check if my server is vulnerable to CVE-2024-41092?
Run 'uname -r' and check if the output shows a version between 6.7.0 and 6.9.7. If so, your system is vulnerable. You can also run 'grep -i 'Unable to pin.*fence' /var/log/kern.log' to see if the issue has already manifested.
Does Defensia detect CVE-2024-41092?
Yes — Defensia's CVE advisory scanner compares installed kernel versions against the NVD database. If a vulnerable kernel version is detected on a monitored server, CVE-2024-41092 will appear in your dashboard with remediation steps and affected component details.
Related Kernel CVEs
References
- https://git.kernel.org/stable/c/06dec31a0a5112a91f49085e8a8fa1a82296d5c7
- https://git.kernel.org/stable/c/29c0fdf49078ab161570d3d1c6e13d66f182717d
- https://git.kernel.org/stable/c/414f4a31f7a811008fd9a33b06216b060bad18fc
- https://git.kernel.org/stable/c/996c3412a06578e9d779a16b9e79ace18125ab50
- https://git.kernel.org/stable/c/ca0fabd365a27a94a36e68a7a02df8ff3c13dac6
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