[PATCH v7 1/3] efi/x86: Fix EFI memory map corruption with kexec
Dave Young
dyoung at redhat.com
Tue Jun 4 18:52:09 PDT 2024
> > ...
> > if (efi.memmap.flags & (EFI_MEMMAP_MEMBLOCK | EFI_MEMMAP_SLAB)) {
> > __efi_memmap_free(efi.memmap.phys_map,
> > efi.memmap.desc_size * efi.memmap.nr_map, efi.memmap.flags);
> > }
>
> From your debugging the memmap should not be freed. This piece of
> code was added in below commit, added Dan Williams in cc list:
> commit f0ef6523475f18ccd213e22ee593dfd131a2c5ea
> Author: Dan Williams <dan.j.williams at intel.com>
> Date: Mon Jan 13 18:22:44 2020 +0100
>
> efi: Fix efi_memmap_alloc() leaks
>
> With efi_fake_memmap() and efi_arch_mem_reserve() the efi table may be
> updated and replaced multiple times. When that happens a previous
> dynamically allocated efi memory map can be garbage collected. Use the
> new EFI_MEMMAP_{SLAB,MEMBLOCK} flags to detect when a dynamically
> allocated memory map is being replaced.
>
Dan, probably those regions should be freed only for "fake" memmap?
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