Messages in this thread | | | Date | Wed, 29 Jul 2015 17:37:52 +0800 | From | Dave Young <> | Subject | Re: [PATCH] x86/mm, efi: Check for valid image type |
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Hi,
> > > As you pointed out above, a wild pointer could cause a > > WARN from early_ioremap. We need to never follow the pointer in the > > first place after a kexec, unless we have some way to know that it's > > actually valid. > > So you assume that the information from ACPI is always correct then? > The pointer is correct, the information it points to is no longer. > > If we run always under EFI then it looks like the variable efi_setup > which is checked in efi_enter_virtual_mode() is 0 during normal boot > and != 0 on kexec entry. This hint is set via setup_data / SETUP_EFI > since commit 1fec053369 ("x86/efi: Pass necessary EFI data for kexec > via setup_data"). So maybe we could use this to check if we run under > kexec or not.
Not sure if BGRT is useful in kexec kernel, it seems not worth to copy it between kernels.
IMO just return in case if (efi_setup) is true make sense.
Thanks Dave
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