Bug 2536667 (CVE-2026-90348)

Summary: CVE-2026-90348 kernel: wifi: ath10k: snoc: use memcpy_fromio() for MSA ramdump
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's ath10k snoc wireless driver. When collecting a firmware crash dump on arm64 systems, the `ath10k_msa_dump_memory()` function uses `memcpy()` to copy data from a memory region that does not permit unaligned accesses. This unaligned memory access triggers a kernel crash, leading to a Denial of Service (DoS) and preventing the capture of important firmware debugging information.
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Description OSIDB Bzimport 2026-09-17 19:04:01 UTC 
In the Linux kernel, the following vulnerability has been resolved:

wifi: ath10k: snoc: use memcpy_fromio() for MSA ramdump

On WCN3990/SNOC the MSA region is mapped with devm_memremap(MEMREMAP_WT).
On arm64 such a mapping is not Normal-cacheable, so unaligned accesses to
it are not permitted. ath10k_msa_dump_memory() copies the region with a
plain memcpy(), whose optimized __pi_memcpy_generic implementation issues
wide/unaligned loads. This triggers an alignment fault (FSC=0x21) Oops in
ath10k_snoc_fw_crashed_dump() while collecting the devcoredump:

  Unable to handle kernel paging request ... FSC=0x21: alignment fault
  pc : __pi_memcpy_generic
  lr : ath10k_snoc_fw_crashed_dump [ath10k_snoc]

The Oops both leaves the firmware RAM dump buffer zeroed (no dump is
captured) and crashes the kernel, which in turn breaks modem SSR
recovery.

Use memcpy_fromio(), which only performs accesses that are valid for such
a device-memory mapping. The generic memcpy_fromio() implementation aligns
the source before issuing word-sized reads and stores the destination with
put_unaligned(), so it is also safe for the coherent DMA allocation used on
the non-reserved-memory path. ath11k and ath12k use the same pattern
when copying target memory into crash dumps, so call it unconditionally
here too.
The MEMREMAP_WT pointer is a plain void *, so an explicit __iomem cast is
needed; use __force to keep sparse happy.

Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.3.7.c5-00107-QCAHLSWMTPL-1
Comment 1 gkamathe 2026-09-22 05:58:56 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90348.mbox