Executive brief
The Linux kernel on Renesas Ironhide ARM64 systems uses a DBSC5 DRAM controller that protects memory with inline error-correcting code (ECC). Without proper reservation of ECC carveout areas, the operating system could allocate and overwrite memory regions required by the ECC controller, causing system instability and data corruption during high memory utilization.
Technical details
This is a memory safety issue in the ARM64 device tree configuration for Renesas Ironhide boards. The DBSC5 DRAM controller reserves portions of DRAM for inline ECC operations, but these regions were not properly marked as reserved-memory in the device tree. As a result, the Linux kernel could allocate and corrupt these areas during high DRAM utilization. The fix adds device tree entries marking eight ECC carveout regions as no-map reserved memory, preventing the kernel from accessing them. This is a configuration/descriptive fix that does not involve patching vulnerable code logic but rather ensuring proper memory layout declaration.
Affected products
- Linux Linux Kernel arm64 with Renesas Ironhide (r8a78000)
Timeline
- 2026-09-04: disclosed
- 2026-07-14: patched: Fix committed to mainline