Description
In the Linux kernel, the following vulnerability has been resolved:
nvmet: fix max_qid race between configfs and controller allocation
The function nvmet_subsys_attr_qid_max_store() can race against
nvmet_alloc_ctrl() when a subsystem's max_qid limit is modified.
Suppose max_qid is currently 64. If nvmet_alloc_ctrl() executes:
ctrl->sqs = kzalloc_objs(struct nvmet_sq *, subsys->max_qid + 1);
and at this exact point, a userspace process changes max_qid to 128,
nvmet_subsys_attr_qid_max_store() will set the new max_qid value. It
attempts to delete active controllers to force a reconnect, but the
new controller won't be deleted because it hasn't been added to the
subsys->ctrls list yet.
nvmet_alloc_ctrl() then proceeds and adds the new controller to the
subsys->ctrls list. Later, when nvmet_install_queue() is called, it
will see max_qid set to 128, but the memory allocated for sqs is only
sized for 64 entries. This results in a KASAN out-of-bounds warning
and potential memory corruptions.
Fix this by protecting the queue allocations and list insertion in
nvmet_alloc_ctrl() with down_read(&nvmet_config_sem). Because
nvmet_subsys_attr_qid_max_store() acquires down_write(&nvmet_config_sem)
to modify the attribute, this safely prevents the configfs writer from
modifying max_qid during controller creation.
Copy the max_qid from the subsystem to the controller's structure
during the allocation; ctrl->max_qid never changes as long as the
controller remains in LIVE state, so this will prevent similar race
conditions.
nvmet: fix max_qid race between configfs and controller allocation
The function nvmet_subsys_attr_qid_max_store() can race against
nvmet_alloc_ctrl() when a subsystem's max_qid limit is modified.
Suppose max_qid is currently 64. If nvmet_alloc_ctrl() executes:
ctrl->sqs = kzalloc_objs(struct nvmet_sq *, subsys->max_qid + 1);
and at this exact point, a userspace process changes max_qid to 128,
nvmet_subsys_attr_qid_max_store() will set the new max_qid value. It
attempts to delete active controllers to force a reconnect, but the
new controller won't be deleted because it hasn't been added to the
subsys->ctrls list yet.
nvmet_alloc_ctrl() then proceeds and adds the new controller to the
subsys->ctrls list. Later, when nvmet_install_queue() is called, it
will see max_qid set to 128, but the memory allocated for sqs is only
sized for 64 entries. This results in a KASAN out-of-bounds warning
and potential memory corruptions.
Fix this by protecting the queue allocations and list insertion in
nvmet_alloc_ctrl() with down_read(&nvmet_config_sem). Because
nvmet_subsys_attr_qid_max_store() acquires down_write(&nvmet_config_sem)
to modify the attribute, this safely prevents the configfs writer from
modifying max_qid during controller creation.
Copy the max_qid from the subsystem to the controller's structure
during the allocation; ctrl->max_qid never changes as long as the
controller remains in LIVE state, so this will prevent similar race
conditions.
Published:
2026-09-17
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
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References
History
Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: nvmet: fix max_qid race between configfs and controller allocation The function nvmet_subsys_attr_qid_max_store() can race against nvmet_alloc_ctrl() when a subsystem's max_qid limit is modified. Suppose max_qid is currently 64. If nvmet_alloc_ctrl() executes: ctrl->sqs = kzalloc_objs(struct nvmet_sq *, subsys->max_qid + 1); and at this exact point, a userspace process changes max_qid to 128, nvmet_subsys_attr_qid_max_store() will set the new max_qid value. It attempts to delete active controllers to force a reconnect, but the new controller won't be deleted because it hasn't been added to the subsys->ctrls list yet. nvmet_alloc_ctrl() then proceeds and adds the new controller to the subsys->ctrls list. Later, when nvmet_install_queue() is called, it will see max_qid set to 128, but the memory allocated for sqs is only sized for 64 entries. This results in a KASAN out-of-bounds warning and potential memory corruptions. Fix this by protecting the queue allocations and list insertion in nvmet_alloc_ctrl() with down_read(&nvmet_config_sem). Because nvmet_subsys_attr_qid_max_store() acquires down_write(&nvmet_config_sem) to modify the attribute, this safely prevents the configfs writer from modifying max_qid during controller creation. Copy the max_qid from the subsystem to the controller's structure during the allocation; ctrl->max_qid never changes as long as the controller remains in LIVE state, so this will prevent similar race conditions. | |
| Title | nvmet: fix max_qid race between configfs and controller allocation | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:07:22.173Z
Reserved: 2026-09-11T19:38:34.793Z
Link: CVE-2026-90206
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:15.700
Modified: 2026-09-17T17:17:15.700
Link: CVE-2026-90206
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.