CVE-2026-63880: drm/amdgpu: fix lock leak on ENOMEM in AMDGPU_GEM_OP_GET_MAPPING_INFO

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-19 · updated 2026-10-30
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix lock leak on ENOMEM in AMDGPU_GEM_OP_GET_MAPPING_INFO The AMDGPU_GEM_OP_GET_MAPPING_INFO branch of amdgpu_gem_op_ioctl() holds three cleanup-tracked resources before calling kvcalloc(): the drm_gem_object reference from drm_gem_object_lookup(), the drm_exec lock on the looked-up GEM via drm_exec_lock_obj(), and the drm_exec lock on the per-process VM root page directory via amdgpu_vm_lock_pd(). All three are released by the out_exec label that every other error path in this function jumps to. The kvcalloc() failure path returns -ENOMEM directly, skipping out_exec and leaking all three. The leaked per-process VM root PD dma_resv lock is the load-bearing leak: any subsequent operation on the same VM (further GEM ops, command-submission, eviction, TTM shrinker callbacks) blocks on the held lock. DRM_IOCTL_AMDGPU_GEM_OP is DRM_AUTH | DRM_RENDER_ALLOW, so this is an unprivileged-local denial of service against the caller's GPU context, reachable by any process with /dev/dri/renderD* access. Route the failure through out_exec so drm_exec_fini() and drm_gem_object_put() run. Reproduced on stock 7.0.0-10, Ryzen 7 5700U / Radeon Vega (Lucienne): the failing ioctl returns -ENOMEM and a second GET_MAPPING_INFO on the same fd then blocks in drm_exec_lock_obj() on the leaked dma_resv. SIGKILL on the caller does not reap the task; the fd-release path during process exit goes through amdgpu_gem_object_close() -> drm_exec_prepare_obj() on the same lock, leaving the task in D state until the box is rebooted. The patched kernel was not rebuilt and re-tested on this hardware; the fix is mechanical. Tested on a single Lucienne / Vega box only. Ziyi Guo posted an independent INT_MAX-bound check for args->num_entries in the same branch [1]; the two patches are complementary and can land in either order. (cherry picked from commit b69d3256d79de15f54c322986ff4da68f1d65b0a)

Affected products

Linux kernel: from 6.18 before 6.18.35; from 6.19 before 7.0.12; 7.1-rc1, 7.1-rc2, 7.1-rc3, 7.1-rc4, 7.1-rc5 — fixed in 6.18.35, 7.0.12
Linux kernel: 6.18 — fixed in 7.1

How to fix

Upgrade to a fixed version: Linux kernel 6.18.35, 7.0.12; Linux kernel 7.1. Check the vendor advisory for mitigations.

References

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