On 08/09/18 at 09:33am, Mike Galbraith wrote: > On Thu, 2018-08-09 at 12:21 +0800, Dave Young wrote: > > Hi Mike, > > > > Thanks for the patch! > > On 08/08/18 at 04:03pm, Mike Galbraith wrote: > > > When booting with efi=noruntime, we call efi_runtime_map_copy() while > > > loading the kdump kernel, and trip over a NULL efi.memmap.map. Avoid > > > that and a useless allocation when the only mapping we can use (1:1) > > > is not available. > > > > At first glance, efi_get_runtime_map_size should return 0 in case > > noruntime. > > What efi does internally at unmap time is to leave everything except > efi.mmap.map untouched, setting it to NULL and turning off EFI_MEMMAP, > rendering efi.mmap.map accessors useless/unsafe without first checking > EFI_MEMMAP. Probably the x86 efi_init should reset nr_map to zero in case runtime is disabled. But let's see how Ard thinks about this and cc linux-efi. As for efi_get_runtime_map_size, it was introduced for x86 kexec use. for copying runtime maps, so I think it is reasonable this function return zero in case no runtime. Thanks Dave -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
