On Mon, Apr 16, 2018 at 10:57:34AM +0800, Dave Young wrote: > On 04/13/18 at 02:27pm, Lee, Chun-Yi wrote: > > When using kdump, SOMETIMES the "size not consistent" warning message > > shows up when the crash kernel boots with early_ioremap_debug parameter: > > > > WARNING: CPU: 0 PID: 0 at ../mm/early_ioremap.c:182 early_iounmap+0x4f/0x12c() > > early_iounmap(ffffffffff200180, 00000118) [0] size not consistent 00000120 > > > > The root cause is that the unmapping size of memory map doesn't > > match with the original size when mapping: > > > > in __efi_memmap_init() > > map.map = early_memremap(phys_map, data->size); > > > > in efi_memmap_unmap() > > size = efi.memmap.desc_size * efi.memmap.nr_map; > > early_memunmap(efi.memmap.map, size); > > > > But the efi.memmap.nr_map is from __efi_memmap_init(). The remainder > > of size was discarded when calculating the nr_map: > > map.nr_map = data->size / data->desc_size; > > > > When the original size of memory map region does not equal to the > > result of multiplication. The "size not consistent" warning > > will be triggered. > > > > This issue sometimes was hit by kdump because kexec set the efi map > > size to align with 16 when loading crash kernel image: > > > > in bzImage64_load() > > efi_map_sz = efi_get_runtime_map_size(); > > efi_map_sz = ALIGN(efi_map_sz, 16); > > > > This patch changes the logic in the unmapping function. Using the > > end address of map to calcuate original size. > > > > Thank Randy Wright for his report and testing. And also thank > > Takashi Iwai for his help to trace issue. > > Good catch. The kexec code need to be fixed to use a separate buffer so > avoid the alignment like what kexec-tools did. I can submit a fix for > that. > Thanks! > But this issue could be a potential issue even if kexec get fixed so it > looks worth a fix in efi code as well. How about mapping only nr_maps > *desc_size in __efi_memmap_init? It looks easier to understand. > Takashi has another patch as you said. Finally I sent this patch because it's smaller. Thanks a lot! Joey Lee -- 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
