CVE-2026-43410

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

firmware: stratix10-rsu: Fix NULL pointer dereference when RSU is disabled

When the Remote System Update (RSU) isn't enabled in the First Stage Boot Loader (FSBL), the driver encounters a NULL pointer dereference when excute svcnormaltosecurethread() thread, resulting in a kernel panic:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 Mem abort info: ... Data abort info: ... [0000000000000008] user address but activemm is swapper Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 0 UID: 0 PID: 79 Comm: svcsmchvcthr Not tainted 6.19.0-rc8-yocto-standard+ #59 PREEMPT Hardware name: SoCFPGA Stratix 10 SoCDK (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : svcnormaltosecurethread+0x38c/0x990 lr : svcnormaltosecurethread+0x144/0x990 ... Call trace: svcnormaltosecurethread+0x38c/0x990 (P) kthread+0x150/0x210 retfromfork+0x10/0x20 Code: 97cfc113 f9400260 aa1403e1 f9400400 (f9400402) ---[ end trace 0000000000000000 ]---

The issue occurs because rsusendasyncmsg() fails when RSU is not enabled in firmware, causing the channel to be freed via stratix10svcfreechannel(). However, the probe function continues execution and registers svcnormaltosecurethread(), which subsequently attempts to access the already-freed channel, triggering the NULL pointer dereference.

Fix this by properly cleaning up the async client and returning early on failure, preventing the thread from being used with an invalid channel.