Re: Patch "purgatory: fix disabling debug info" has been added to the 5.15-stable tree

Re: Patch "purgatory: fix disabling debug info" has been added to the 5.15-stable tree

[Alyssa Ross]

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On Mon, Apr 17, 2023 at 09:27:22PM -0400, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
>
>     purgatory: fix disabling debug info
>
> to the 5.15-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
>
> The filename of the patch is:
>      purgatory-fix-disabling-debug-info.patch
> and it can be found in the queue-5.15 subdirectory.
>
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.

There's no need for this patch on 5.15, as the regression it fixes was
only introduced in 6.0.  It won't do any harm though — is it considered
good practice to keep the code in sync between stable kernels to make
backports of other patches easier?  If so, it would make sense to
backport after all.

> commit 618ea690941689fe28fa9c150f90bb096db5f8a5
> Author: Alyssa Ross <hi@alyssa.is>
> Date:   Sun Mar 26 18:21:21 2023 +0000
>
>     purgatory: fix disabling debug info
>
>     [ Upstream commit d83806c4c0cccc0d6d3c3581a11983a9c186a138 ]
>
>     Since 32ef9e5054ec, -Wa,-gdwarf-2 is no longer used in KBUILD_AFLAGS.
>     Instead, it includes -g, the appropriate -gdwarf-* flag, and also the
>     -Wa versions of both of those if building with Clang and GNU as.  As a
>     result, debug info was being generated for the purgatory objects, even
>     though the intention was that it not be.
>
>     Fixes: 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files")
>     Signed-off-by: Alyssa Ross <hi@alyssa.is>
>     Cc: stable@vger.kernel.org
>     Acked-by: Nick Desaulniers <ndesaulniers@google.com>
>     Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
>     Signed-off-by: Sasha Levin <sashal@kernel.org>
>
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 95ea17a9d20cb..1d6ccd4214d5a 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -64,8 +64,7 @@ CFLAGS_sha256.o			+= $(PURGATORY_CFLAGS)
>  CFLAGS_REMOVE_string.o		+= $(PURGATORY_CFLAGS_REMOVE)
>  CFLAGS_string.o			+= $(PURGATORY_CFLAGS)
>
> -AFLAGS_REMOVE_setup-x86_$(BITS).o	+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_entry64.o			+= -Wa,-gdwarf-2
> +asflags-remove-y		+= $(foreach x, -g -gdwarf-4 -gdwarf-5, $(x) -Wa,$(x))
>
>  $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
>  		$(call if_changed,ld)

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Re: Patch "purgatory: fix disabling debug info" has been added to the 5.15-stable tree

[Sasha Levin]

On Tue, Apr 18, 2023 at 10:39:51AM +0000, Alyssa Ross wrote:
>On Mon, Apr 17, 2023 at 09:27:22PM -0400, Sasha Levin wrote:
>> This is a note to let you know that I've just added the patch titled
>>
>>     purgatory: fix disabling debug info
>>
>> to the 5.15-stable tree which can be found at:
>>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
>>
>> The filename of the patch is:
>>      purgatory-fix-disabling-debug-info.patch
>> and it can be found in the queue-5.15 subdirectory.
>>
>> If you, or anyone else, feels it should not be added to the stable tree,
>> please let <stable@vger.kernel.org> know about it.
>
>There's no need for this patch on 5.15, as the regression it fixes was
>only introduced in 6.0.  It won't do any harm though — is it considered
>good practice to keep the code in sync between stable kernels to make
>backports of other patches easier?  If so, it would make sense to
>backport after all.

It went into 5.15 because the patch in question says:

>>     Fixes: 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files")

In the 5.15 tree, we have 0ee2f0567a56 ("Makefile.debug: re-enable debug
info for .S files") and so I've also added this patch into 5.15.

-- 
Thanks,
Sasha

Re: Patch "purgatory: fix disabling debug info" has been added to the 5.15-stable tree

[Greg KH]

On Tue, Apr 18, 2023 at 10:39:51AM +0000, Alyssa Ross wrote:
> On Mon, Apr 17, 2023 at 09:27:22PM -0400, Sasha Levin wrote:
> > This is a note to let you know that I've just added the patch titled
> >
> >     purgatory: fix disabling debug info
> >
> > to the 5.15-stable tree which can be found at:
> >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> >
> > The filename of the patch is:
> >      purgatory-fix-disabling-debug-info.patch
> > and it can be found in the queue-5.15 subdirectory.
> >
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> 
> There's no need for this patch on 5.15, as the regression it fixes was
> only introduced in 6.0.

Not according to the information in this commit, which says:

Fixes: 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files")

And that commit is in the following releases:

	4.19.264 5.4.221 5.10.152 5.15.76 5.19.12 6.0

So it should be also in 5.4.y and 4.19.y, right?

thanks,

greg k-h

Re: Patch "purgatory: fix disabling debug info" has been added to the 5.15-stable tree

[Alyssa Ross]

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On Tue, Apr 18, 2023 at 01:19:39PM +0200, Greg KH wrote:
> On Tue, Apr 18, 2023 at 10:39:51AM +0000, Alyssa Ross wrote:
> > On Mon, Apr 17, 2023 at 09:27:22PM -0400, Sasha Levin wrote:
> > > This is a note to let you know that I've just added the patch titled
> > >
> > >     purgatory: fix disabling debug info
> > >
> > > to the 5.15-stable tree which can be found at:
> > >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > >
> > > The filename of the patch is:
> > >      purgatory-fix-disabling-debug-info.patch
> > > and it can be found in the queue-5.15 subdirectory.
> > >
> > > If you, or anyone else, feels it should not be added to the stable tree,
> > > please let <stable@vger.kernel.org> know about it.
> >
> > There's no need for this patch on 5.15, as the regression it fixes was
> > only introduced in 6.0.
>
> Not according to the information in this commit, which says:
>
> Fixes: 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files")
>
> And that commit is in the following releases:
>
> 	4.19.264 5.4.221 5.10.152 5.15.76 5.19.12 6.0
>
> So it should be also in 5.4.y and 4.19.y, right?

Okay, it turns out that it should be included in 5.15.y and 5.10.y,
and I was missing it because unlike in 6.x, in 5.15.y and 5.10.y the
problem only affects Clang builds (using the integrated assembler),
since their versions of the commit in the Fixes tag are different to
the ones in 6.1.y and 6.2.y.

As you point out, 5.4.y and 4.19.y are also affected, and in fact
4.14.y is too.  But porting to these kernels is harder, because they
don't include 15d5761ad31d, which introduced asflags-remove-y.

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