CVE-2026-53204

In the Linux kernel, the following vulnerability has been resolved:

firmware: stratix10-rsu: Fix NULL deref on rsu_send_msg() timeout in probe

rsu_send_msg() can return -ETIMEDOUT when wait_for_completion_interruptible_timeout() fires while the SMC call is still pending. In stratix10_rsu_probe(), the error paths for COMMAND_RSU_DCMF_VERSION, COMMAND_RSU_DCMF_STATUS, COMMAND_RSU_MAX_RETRY and COMMAND_RSU_GET_SPT_TABLE call stratix10_svc_free_channel() - which sets chan->scl to NULL - but then fall through and queue the next request on the same channel. The next svc kthread that runs will dereference pdata->chan->scl in its receive callback path, triggering a NULL pointer dereference identical to the one fixed by commit c45f7263100c (firmware: stratix10-rsu: Fix NULL pointer dereference when RSU is disabled) for the COMMAND_RSU_STATUS path.

Apply the same cleanup pattern to the remaining failure paths: remove the async client, free the channel, and return early so no further messages are queued on a channel whose scl has been cleared.

While at it, clean up stratix10_rsu_probe() in two ways without changing behavior:

• Drop redundant zero-initialization of fields already cleared by devm_kzalloc(): client.receive_cb, status.* and spt0/1_address (INVALID_SPT_ADDRESS is 0x0).

• Replace five identical 3-line error-cleanup blocks (stratix10_svc_remove_async_client() + stratix10_svc_free_channel() + return ret) with goto labels (remove_async_client, free_channel), matching the standard kernel resource-unwinding pattern and making it easier to extend the probe sequence without forgetting matching cleanup.

Also move init_completion() next to mutex_init() so sync-primitive initialization is grouped before anything that could trigger a callback.

v2: Add a minor clean-up of the function stratix10_rsu_probe() to have a centralize exit for all the rsu_send_async_msg() and rsu_send_msg().

Weakness

The product dereferences a pointer that it expects to be valid but is NULL.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/6bc249d324241c64118a3018124798c28e2950f7
• https://git.kernel.org/stable/c/bfd2eb9bba548a8f63c3339bb1fb9a2031a42d86