RE: linux-next: build failure after merge of the tip tree

Chen, Yu C
2016-09-29T15:54:37Z

Hi,

> -----Original Message-----
> From: Rafael J. Wysocki [mailto:rjw@rjwysocki.net]
> Sent: Thursday, September 29, 2016 8:25 PM
> To: Stephen Rothwell
> Cc: Thomas Gleixner; Ingo Molnar; H. Peter Anvin; Peter Zijlstra; linux-
> next@vger.kernel.org; linux-kernel@vger.kernel.org; Denys Vlasenko; Chen, Yu
> C
> Subject: Re: linux-next: build failure after merge of the tip tree
>
> On Thursday, September 29, 2016 01:20:07 PM Stephen Rothwell wrote:
> > Hi all,
> >
> > After merging the tip tree, today's linux-next build (x86_64
> > allmodconfig) failed like this:
> >
> > arch/x86/power/hibernate_64.c: In function 'hibernation_e820_save':
> > arch/x86/power/hibernate_64.c:236:15: error: passing argument 1 of
> 'get_e820_md5' from incompatible pointer type [-Werror=incompatible-
> pointer-types]
> > get_e820_md5(&e820_saved, buf);
> > ^
> > arch/x86/power/hibernate_64.c:203:12: note: expected 'struct e820map *'
> but argument is of type 'struct e820map **'
> > static int get_e820_md5(struct e820map *map, void *buf)
> > ^
> > arch/x86/power/hibernate_64.c: In function 'hibernation_e820_mismatch':
> > arch/x86/power/hibernate_64.c:249:21: error: passing argument 1 of
> 'get_e820_md5' from incompatible pointer type [-Werror=incompatible-
> pointer-types]
> > ret = get_e820_md5(&e820_saved, result);
> > ^
> > arch/x86/power/hibernate_64.c:203:12: note: expected 'struct e820map *'
> but argument is of type 'struct e820map **'
> > static int get_e820_md5(struct e820map *map, void *buf)
> > ^
> >
> > Caused by commit
> >
> > 475339684ef1 ("x86/e820: Prepare e280 code for switch to dynamic
> > storage")
> >
> > interacting with commit
> >
> > 6f95ad2b6162 ("PM / hibernate: Verify e820 memory map by MD5
> > digest")
> >
> > from the pm tree.
> >
> > I have applied the following merge fix patch:
> >
> > From: Stephen Rothwell <sfr@canb.auug.org.au>
> > Date: Thu, 29 Sep 2016 13:13:45 +1000
> > Subject: [PATCH] pm/hibernate: merge fix for type of e820_saved
> > changing
> >
> > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
> > ---
> > arch/x86/power/hibernate_64.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/power/hibernate_64.c
> > b/arch/x86/power/hibernate_64.c index 72f2c9531b03..904048f7a9c9
> > 100644
> > --- a/arch/x86/power/hibernate_64.c
> > +++ b/arch/x86/power/hibernate_64.c
> > @@ -233,7 +233,7 @@ static int get_e820_md5(struct e820map *map, void
> > *buf)
> >
> > static void hibernation_e820_save(void *buf) {
> > - get_e820_md5(&e820_saved, buf);
> > + get_e820_md5(e820_saved, buf);
> > }
> >
> > static bool hibernation_e820_mismatch(void *buf) @@ -246,7 +246,7 @@
> > static bool hibernation_e820_mismatch(void *buf)
> > if (!memcmp(result, buf, MD5_DIGEST_SIZE))
> > return false;
> >
> > - ret = get_e820_md5(&e820_saved, result);
> > + ret = get_e820_md5(e820_saved, result);
> > if (ret)
> > return true;
> >
> >
>
> Looks good to me, thanks Stephen!
>
> Rafael
Thanks for the fix!

I made a double check of the patch :
"x86/e820: Prepare e280 code for switch to dynamic storage"
It looks like this patch has reallocate the e820 & e820_save to their actual size:
+ size = offsetof(struct e820map, map) + sizeof(struct e820entry) * e820->nr_map;
+ n = kmalloc(size, GFP_KERNEL);

however the previous patch to verify the md5 hash during hibernation will
use the original e820_map structure by sizeof(struct e820map), which might
read invalid value after the latest patch applied. I think I need to modify the
hibernation e820 checking patch to only generate md5 digest based on the actual
e820_save size by sizeof(struct e820entry) * e820->nr_map.

I don't have a machine in hand now, will test later and give feedback later. Thanks again!
Yu