Re: [PATCH v3 0/3] LoongArch: Move KASLR to EFI stub to avoid initrd overlap
"Ard Biesheuvel" <[email protected]> Wed, 29 Apr 2026 11:16:01 +0200
| Newsgroups | org.kernel.vger.linux-efi,dev.linux.lists.loongarch,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On Wed, 29 Apr 2026, at 07:13, WANG Rui wrote: > Changes since [v2]: > * Add a new patch to prevent initrd overlap during relocation. > * Revert changes to the CONFIG_RANDOMIZE_BASE_MAX_OFFSET range. > > Changes since [v1]: > * Drop the patch "LoongArch: Allow rdtime_h() and rdtime_l() in > 64-bit builds". > * Use random_get_entropy() instead of rdtime_l(). > > This series addresses a potential overlap issue between the kernel > image and the initrd when KASLR is enabled. > > In the normal boot flow, the bootloader is responsible for loading > both vmlinux and the initrd, and it can guarantee that the two do > not overlap in memory. However, this assumption only holds as long > as neither image changes its location afterwards. > > The in-kernel KASLR implementation breaks that assumption. When the > initrd is placed close to the kernel image, randomizing the kernel > location at runtime may move it into the initrd region, leading to > memory corruption early during boot. > > To fix this, this series moves the KASLR logic out of the kernel > proper and into the EFI stub. With this change, the final placement > of both the kernel image and the initrd is determined by the EFI > memory allocator. This ensures that the two allocations are > coordinated and cannot overlap. > > Functionally, the kernel still supports KASLR as before, but the > randomization now happens before the kernel is entered, rather than > during early kernel relocation. > > [v2]: https://lore.kernel.org/loongarch/[email protected] > [v1]: https://lore.kernel.org/loongarch/[email protected] > > WANG Rui (3): > efi/loongarch: Randomize kernel preferred address for KASLR > LoongArch: Skip relocation-time KASLR if it has already been applied > LoongArch: Avoid initrd overlap during kernel relocation > For the series, Acked-by: Ard Biesheuvel <[email protected]> Feel free to take the EFI changes via the LoongArch tree.