[PATCH 0/1] x86/purgatory: Fix Makefile bug

[PATCH 0/1] x86/purgatory: Fix Makefile bug

[Philipp Rudo]

Hi everybody,

when i moved the purgatories sha256 implementation to common code, i forgot
to add FORCE to the new Makefile target. This patch fixes it.

Note: There is an equivalent bug in the s390 purgatory. The fix for that
will go upstream via Martin.

Thanks
Philipp

Philipp Rudo (1):
  x86/purgatory: Add missing FORCE to Makefile target

 arch/x86/purgatory/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.16.4


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

[PATCH 1/1] x86/purgatory: Add missing FORCE to Makefile target

[Philipp Rudo]

Without FORCE make does not detect changes only made to the command line
options. So object files might not be re-built even when they should be.
Fix this by adding FORCE where it is missing.

Fixes: df6f2801f511 ("kernel/kexec_file.c: move purgatories sha256 to common code")
Cc: <stable@vger.kernel.org> # 4.17
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
---
 arch/x86/purgatory/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 2e9ee023e6bc..81a8e33115ad 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -6,7 +6,7 @@ purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string
 targets += $(purgatory-y)
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
 
-$(obj)/sha256.o: $(srctree)/lib/sha256.c
+$(obj)/sha256.o: $(srctree)/lib/sha256.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
 LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib
-- 
2.16.4


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: [PATCH 0/1] x86/purgatory: Fix Makefile bug

[Dave Young]

On 07/04/18 at 01:00pm, Philipp Rudo wrote:
> Hi everybody,
> 
> when i moved the purgatories sha256 implementation to common code, i forgot
> to add FORCE to the new Makefile target. This patch fixes it.

Hi Philipp,

Do you have the exact steps of how to reproduce your problem?

> 
> Note: There is an equivalent bug in the s390 purgatory. The fix for that
> will go upstream via Martin.
> 
> Thanks
> Philipp
> 
> Philipp Rudo (1):
>   x86/purgatory: Add missing FORCE to Makefile target
> 
>  arch/x86/purgatory/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> -- 
> 2.16.4
> 

Thanks
Dave

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: [PATCH 0/1] x86/purgatory: Fix Makefile bug

[Philipp Rudo]

Hi Dave,

On Thu, 5 Jul 2018 14:46:20 +0800
Dave Young <dyoung@redhat.com> wrote:

> On 07/04/18 at 01:00pm, Philipp Rudo wrote:
> > Hi everybody,
> > 
> > when i moved the purgatories sha256 implementation to common code, i forgot
> > to add FORCE to the new Makefile target. This patch fixes it.  
> 
> Hi Philipp,
> 
> Do you have the exact steps of how to reproduce your problem?

I only tested it on s390, but on x86 it should work the same way.

- Build the kernel without the fix
- Add some flag to the purgatories KBUILD_CFLAGS,I used
  -fno-asynchronous-unwind-tables
- Re-build the kernel

When you look at make's output you see that sha256.o is not re-build in the
last step. Also readelf -S still shows the .eh_frame section for sha256.o.

With the fix sha256.o is re-build in the last step.

Hope that helps.

Thanks
Philipp

> > 
> > Note: There is an equivalent bug in the s390 purgatory. The fix for that
> > will go upstream via Martin.
> > 
> > Thanks
> > Philipp
> > 
> > Philipp Rudo (1):
> >   x86/purgatory: Add missing FORCE to Makefile target
> > 
> >  arch/x86/purgatory/Makefile | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > -- 
> > 2.16.4
> >   
> 
> Thanks
> Dave
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: [PATCH 0/1] x86/purgatory: Fix Makefile bug

[Dave Young]

Hi Philipp,

On 07/05/18 at 10:43am, Philipp Rudo wrote:
> Hi Dave,
> 
> On Thu, 5 Jul 2018 14:46:20 +0800
> Dave Young <dyoung@redhat.com> wrote:
> 
> > On 07/04/18 at 01:00pm, Philipp Rudo wrote:
> > > Hi everybody,
> > > 
> > > when i moved the purgatories sha256 implementation to common code, i forgot
> > > to add FORCE to the new Makefile target. This patch fixes it.  
> > 
> > Hi Philipp,
> > 
> > Do you have the exact steps of how to reproduce your problem?
> 
> I only tested it on s390, but on x86 it should work the same way.
> 
> - Build the kernel without the fix
> - Add some flag to the purgatories KBUILD_CFLAGS,I used
>   -fno-asynchronous-unwind-tables
> - Re-build the kernel
> 
> When you look at make's output you see that sha256.o is not re-build in the
> last step. Also readelf -S still shows the .eh_frame section for sha256.o.
> 
> With the fix sha256.o is re-build in the last step.
> 
> Hope that helps.

Thanks for explanation.

For the patch:
Acked-by: Dave Young <dyoung@redhat.com>

Thanks
Dave

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: [PATCH 0/1] x86/purgatory: Fix Makefile bug

[Philipp Rudo]

Hi Andrew,

can you send this fix to Linus like the original patch?

Can you also tell me if the bug is severe enough to go to stable? For
productive systems the bug shouldn't cause any problem because they are usually
build from scratch. For developers however, it can cause quite a pain while
debugging.

@Dave: Thanks for looking into this.

Thanks
Philipp


On Fri, 6 Jul 2018 16:30:29 +0800
Dave Young <dyoung@redhat.com> wrote:

> Hi Philipp,
> 
> On 07/05/18 at 10:43am, Philipp Rudo wrote:
> > Hi Dave,
> > 
> > On Thu, 5 Jul 2018 14:46:20 +0800
> > Dave Young <dyoung@redhat.com> wrote:
> >   
> > > On 07/04/18 at 01:00pm, Philipp Rudo wrote:  
> > > > Hi everybody,
> > > > 
> > > > when i moved the purgatories sha256 implementation to common code, i forgot
> > > > to add FORCE to the new Makefile target. This patch fixes it.    
> > > 
> > > Hi Philipp,
> > > 
> > > Do you have the exact steps of how to reproduce your problem?  
> > 
> > I only tested it on s390, but on x86 it should work the same way.
> > 
> > - Build the kernel without the fix
> > - Add some flag to the purgatories KBUILD_CFLAGS,I used
> >   -fno-asynchronous-unwind-tables
> > - Re-build the kernel
> > 
> > When you look at make's output you see that sha256.o is not re-build in the
> > last step. Also readelf -S still shows the .eh_frame section for sha256.o.
> > 
> > With the fix sha256.o is re-build in the last step.
> > 
> > Hope that helps.  
> 
> Thanks for explanation.
> 
> For the patch:
> Acked-by: Dave Young <dyoung@redhat.com>
> 
> Thanks
> Dave
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec