Messages in this thread | | | Date | Fri, 4 May 2018 15:29:16 +0800 | From | joeyli <> | Subject | Re: [PATCH] efi: Fix the size not consistent issue when unmapping memory map |
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Hi Ard,
On Thu, May 03, 2018 at 02:05:51PM +0200, Ard Biesheuvel wrote: > On 2 May 2018 at 08:17, Lee, Chun-Yi <joeyli.kernel@gmail.com> 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); > > > > Dave Young's a841aa83d patch fixed kexec issue. On UEFI side, this > > patch changes the logic in the unmapping function. Using the end > > address of map to calcuate original size. > > > > Why do we still need this patch? I.e., in which circumstances will > efi_memory_map_data::size assume a value that is rounded up or > otherwise incorrect? >
There have no other case except kexec. But I think that it's better to sync mapping/unmapping size between __efi_memmap_init() and efi_memmap_unmap().
Thanks Joey Lee
> > Thank Randy Wright for his report and testing. And also thank > > Takashi Iwai for his help to trace issue. > > > > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > Cc: Takashi Iwai <tiwai@suse.de> > > Cc: Vivek Goyal <vgoyal@redhat.com> > > Cc: Ingo Molnar <mingo@redhat.com> > > Tested-by: Randy Wright <rwright@hpe.com> > > Signed-off-by: "Lee, Chun-Yi" <jlee@suse.com> > > --- > > drivers/firmware/efi/memmap.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c > > index 5fc7052..1f592d8 100644 > > --- a/drivers/firmware/efi/memmap.c > > +++ b/drivers/firmware/efi/memmap.c > > @@ -121,7 +121,7 @@ void __init efi_memmap_unmap(void) > > if (!efi.memmap.late) { > > unsigned long size; > > > > - size = efi.memmap.desc_size * efi.memmap.nr_map; > > + size = efi.memmap.map_end - efi.memmap.map; > > early_memunmap(efi.memmap.map, size); > > } else { > > memunmap(efi.memmap.map); > > -- > > 2.10.2 > >
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