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SubjectRE: [PATCH][v10] PM / hibernate: Verify the consistent of e820 memory map by md5 digest
Date
Hi,
Sorry for late response, I missed the thread in mailbox,

> -----Original Message-----
> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
> Rafael J. Wysocki
> Sent: Monday, September 19, 2016 7:46 PM
> To: Chen, Yu C
> Cc: Linux PM; the arch/x86 maintainers; Linux Kernel Mailing List; Thomas
> Gleixner; Ingo Molnar; H. Peter Anvin; Wysocki, Rafael J; Pavel Machek; Lee
> Chun-Yi; Borislav Petkov
> Subject: Re: [PATCH][v10] PM / hibernate: Verify the consistent of e820
> memory map by md5 digest
>
> On Fri, Sep 9, 2016 at 2:21 PM, Chen Yu <yu.c.chen@intel.com> wrote:
> > On some platforms, there is occasional panic triggered when trying to
> > resume from hibernation, a typical panic looks like:
>
> [cut]
>
> > @@ -211,10 +292,15 @@ int arch_hibernation_header_save(void *addr,
> unsigned int max_size)
> > */
> > int arch_hibernation_header_restore(void *addr) {
> > + bool e820_mismatch = false;
>
> The extra local variable can be avoided if you structure the code slightly
> differently.
>
> > struct restore_data_record *rdr = addr;
> >
> > restore_jump_address = rdr->jump_address;
> > jump_address_phys = rdr->jump_address_phys;
> > restore_cr3 = rdr->cr3;
> > - return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;
> > +
> > + e820_mismatch = hibernation_e820_mismatch(rdr->e820_digest);
>
> Also calling hibernation_e820_mismatch() before checking rdr->magic may not
> be useful at all.
>
Yes.
> > +
> > + return (rdr->magic == RESTORE_MAGIC) ?
> > + (e820_mismatch ? -ENODEV : 0) : -EINVAL;
>
> So what about:
>
> if (rdr->magic != RESTORE_MAGIC)
> return -EINVAL;
>
> if (hibernation_e820_mismatch(rdr->e820_digest))
> return -ENODEV;
>
> return 0;
>
>
Ok, will change it to this one. Thanks.
> > }
> > --
>
> Thanks,
> Rafael


Thanks,
Yu
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