RE: [PATCH v13 11/11] arm64: Select HAVE_RELIABLE_STACKTRACE

From: "nobuta.keiya@fujitsu.com" <nobuta.keiya@fujitsu.com>
To: "'Madhavan T. Venkataraman'" <madvenka@linux.microsoft.com>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"broonie@kernel.org" <broonie@kernel.org>,
	"jpoimboe@redhat.com" <jpoimboe@redhat.com>,
	"ardb@kernel.org" <ardb@kernel.org>,
	"sjitindarsingh@gmail.com" <sjitindarsingh@gmail.com>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"will@kernel.org" <will@kernel.org>,
	"jmorris@namei.org" <jmorris@namei.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v13 11/11] arm64: Select HAVE_RELIABLE_STACKTRACE
Date: Wed, 26 Jan 2022 10:20:16 +0000	[thread overview]
Message-ID: <TY2PR01MB5257BE671A481D81F1A40E0185209@TY2PR01MB5257.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <825b8b72-c746-ba24-7142-3fff481e82d6@linux.microsoft.com>

> I have not seen any activity on that in a long time. IIRC, Julien quit RedHat.
> I don't know if anyone else has taken over this work in RedHat.
> 
> Sorry, I don't have any more information.
> 
> Madhavan

Thanks for your information.

By the way, I'm considering test code for arch_stack_walk_reliable().
Specifically, I apply Suraj's patch to enable livepatch, and added a function
that sleeps between SYM_CODE_START and SYM_CODE_END, then livepatch
checks if the task has an unreliable stack.
For now my internal test code working correctly, but my Kconfig excludes
STACK_VALIDATION dependency.

It seems that objtool will not be enabled yet, so I would like to test it easier.
If you are already testing with this patch, could you tell me how to do it?

Thanks,
Keiya

> 
> On 1/24/22 23:21, nobuta.keiya@fujitsu.com wrote:
> > Hi Madhavan,
> >
> >> Select HAVE_RELIABLE_STACKTRACE in arm64/Kconfig to allow
> >> arch_stack_walk_reliable() to be used.
> >>
> >> Note that this is conditional upon STACK_VALIDATION which will be
> >> added when frame pointer validation is implemented (say via objtool).
> >
> > I know that Julien Thierry published objtool support for arm64 [1],
> > but I'm not sure if it has been updated. Could you tell me other threads if you know?
> >
> > [1]
> > https://lore.kernel.org/linux-arm-kernel/20210303170932.1838634-1-jthi
> > erry@redhat.com/
> >
> >
> > Thanks,
> > Keiya
> >
> >>
> >> Signed-off-by: Madhavan T. Venkataraman
> >> <madvenka@linux.microsoft.com>
> >> ---
> >>  arch/arm64/Kconfig | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index
> >> f6e333b59314..bc7b3514b563 100644
> >> --- a/arch/arm64/Kconfig
> >> +++ b/arch/arm64/Kconfig
> >> @@ -223,6 +223,7 @@ config ARM64
> >>  	select THREAD_INFO_IN_TASK
> >>  	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
> >>  	select TRACE_IRQFLAGS_SUPPORT
> >> +	select HAVE_RELIABLE_STACKTRACE if FRAME_POINTER &&
> >> +STACK_VALIDATION
> >>  	help
> >>  	  ARM 64-bit (AArch64) Linux support.
> >>
> >> --
> >> 2.25.1
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel