+ Dan because of
f0ef6523475f ("efi: Fix efi_memmap_alloc() leaks")
Thanks Ard.
On Mon, Jun 10, 2024 at 04:09:33PM +0200, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@xxxxxxxxxx>
>
> The logic in __efi_memmap_init() is shared between two different
> execution flows:
> - mapping the EFI memory map early or late into the kernel VA space, so
> that its entries can be accessed;
> - cloning the EFI memory map in order to insert new entries that are
> created as a result of creating a memory reservation
> (efi_arch_mem_reserve())
>
> In the former case, the underlying memory containing the kernel's view
> of the EFI memory map (which may be heavily modified by the kernel
> itself on x86) is not modified at all, and the only thing that changes
> is the virtual mapping of this memory, which is different between early
> and late boot.
>
> In the latter case, an entirely new allocation is created that carries a
> new, updated version of the kernel's view of the EFI memory map. When
> installing this new version, the old version will no longer be
> referenced, and if the memory was allocated by the kernel, it will leak
> unless it gets freed.
>
> The logic that implements this freeing currently lives on the code path
> that is shared between these two use cases, but it should only apply to
> the latter. So move it to the correct spot.
>
> Cc: Ashish Kalra <Ashish.Kalra@xxxxxxx>
> Cc: Dave Young <dyoung@xxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Link: https://lore.kernel.org/all/36ad5079-4326-45ed-85f6-928ff76483d3@xxxxxxx
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> ---
> arch/x86/platform/efi/memmap.c | 5 +++++
> drivers/firmware/efi/memmap.c | 5 -----
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/platform/efi/memmap.c b/arch/x86/platform/efi/memmap.c
> index 4ef20b49eb5e..4990244e5168 100644
> --- a/arch/x86/platform/efi/memmap.c
> +++ b/arch/x86/platform/efi/memmap.c
> @@ -97,6 +97,11 @@ int __init efi_memmap_install(struct efi_memory_map_data *data)
> if (efi_enabled(EFI_PARAVIRT))
> return 0;
>
> + 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);
> +
> return __efi_memmap_init(data);
> }
>
> diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
> index 3365944f7965..3759e95a7407 100644
> --- a/drivers/firmware/efi/memmap.c
> +++ b/drivers/firmware/efi/memmap.c
> @@ -51,11 +51,6 @@ int __init __efi_memmap_init(struct efi_memory_map_data *data)
> return -ENOMEM;
> }
>
> - 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);
> -
> map.phys_map = data->phys_map;
> map.nr_map = data->size / data->desc_size;
> map.map_end = map.map + data->size;
> --
> 2.45.2.505.gda0bf45e8d-goog
>
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
