firmware: arm_scmi: Publish channel state before callbacks
Transport setup can enable callbacks before the setup routine returns.
mailbox_chan_setup() registers the mailbox client with
mbox_request_channel(), and the mailbox controller startup path can enable
interrupt delivery before SCMI mailbox channel state has been published.
Similarly, smc_chan_setup() requests the optional A2P completion IRQ before
the SMC transport has made its cinfo pointer visible.
If a pending or spurious callback fires in those windows, the transport RX
callback can dereference a NULL transport cinfo pointer. Publishing only
the transport-private pointer is not sufficient either: an early callback
can enter the SCMI core before scmi_chan_setup() has assigned
cinfo->handle.
The core derives scmi_info from cinfo->handle in the RX path, so a NULL
handle can still fault even when the transport-private cinfo is valid.
Assign cinfo->handle before invoking the transport setup callback. Publish
the mailbox and SMC transport-private channel state before requesting the
mailbox channels or IRQ, and clear the early-published pointers again on
setup failure. Also unwind mailbox setup devres resources on failure so an
optional RX setup error that is ignored by the core does not leave stale
transport state behind.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
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 |
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| Linux | Linux | affected |
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No data available yet.
No vendor fix or workaround currently provided.
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Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Publish channel state before callbacks Transport setup can enable callbacks before the setup routine returns. mailbox_chan_setup() registers the mailbox client with mbox_request_channel(), and the mailbox controller startup path can enable interrupt delivery before SCMI mailbox channel state has been published. Similarly, smc_chan_setup() requests the optional A2P completion IRQ before the SMC transport has made its cinfo pointer visible. If a pending or spurious callback fires in those windows, the transport RX callback can dereference a NULL transport cinfo pointer. Publishing only the transport-private pointer is not sufficient either: an early callback can enter the SCMI core before scmi_chan_setup() has assigned cinfo->handle. The core derives scmi_info from cinfo->handle in the RX path, so a NULL handle can still fault even when the transport-private cinfo is valid. Assign cinfo->handle before invoking the transport setup callback. Publish the mailbox and SMC transport-private channel state before requesting the mailbox channels or IRQ, and clear the early-published pointers again on setup failure. Also unwind mailbox setup devres resources on failure so an optional RX setup error that is ignored by the core does not leave stale transport state behind. | |
| Title | firmware: arm_scmi: Publish channel state before callbacks | |
| 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: 2026-09-17T16:11:08.360Z
Reserved: 2026-09-17T16:02:15.084Z
Link: CVE-2026-93093
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:18:03.300
Modified: 2026-09-17T17:18:03.300
Link: CVE-2026-93093
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.