drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds
Summary
| CVE | CVE-2026-89809 |
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-16 11:16:46 UTC |
| Updated | 2026-09-16 11:16:46 UTC |
| Description | In 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
| Source | Vendor | Product | Version | Platforms |
|---|
| 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
| Reference | Source | Link | Tags |
|---|
| 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 |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.