drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds

Summary

CVECVE-2026-89809
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 11:16:46 UTC
Updated2026-09-16 11:16:46 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds Reading /sys/kernel/debug/kfd/mqds while a process holds an active KFD queue triggers a NULL pointer dereference because the for loop that calls mqd_mgr->debugfs_show_mqd() is incorrectly placed outside the if (pqn->q) block that initializes mqd_mgr. The queue list can contain entries where pqn->q is NULL (kernel queues where only pqn->kq is valid). In the original code: if (pqn->q) { ... mqd_mgr = q->device->dqm->mqd_mgrs[mqd_type]; size = mqd_mgr->mqd_stride(...); } for (xcc = 0; xcc < num_xccs; xcc++) { // WRONG: outside if block mqd = q->mqd + size * xcc; r = mqd_mgr->debugfs_show_mqd(m, mqd); } When iterating over a queue node where pqn->q is NULL: 1. The if (pqn->q) block is skipped 2. mqd_mgr remains uninitialized (NULL from declaration) 3. The for loop executes anyway 4. mqd_mgr->debugfs_show_mqd(m, mqd) dereferences NULL The crash manifests as: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode RIP: 0010:0x0 Call Trace: pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu] kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu] seq_read_iter+0x132/0x4b0 ... Fix by moving the for loop inside the if (pqn->q) block, so mqd_mgr and related variables are only used when properly initialized. (cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 58e866711b234571b0ce342c43d153a4786b32b8 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 012a026bae0212952b423a842b7e2c0bf21f8e7a git Not specified
CNA Linux Linux affected 7.2.5 semver Not specified
CNA Linux Linux unaffected 7.2.5 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/58e866711b234571b0ce342c43d153a4786b32b8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/012a026bae0212952b423a842b7e2c0bf21f8e7a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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