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Date:   Fri, 10 Aug 2018 15:44:49 -0500
From:   Josh Poimboeuf <jpoimboe@redhat.com>
To:     Torsten Duwe <duwe@lst.de>
Cc:     Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Julien Thierry <julien.thierry@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        AKASHI Takahiro <takahiro.akashi@linaro.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        live-patching@vger.kernel.org
Subject: Re: [PATCH 3/3] arm64: reliable stacktraces
Message-ID: <20180810204449.4asgonydn6yfb6kq@treble>
References: <20180810160043.9E45568C76@newverein.lst.de>
 <20180810160311.C988D68CF4@newverein.lst.de>
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On Fri, Aug 10, 2018 at 06:03:11PM +0200, Torsten Duwe wrote:
> This is more an RFC in the original sense: is this basically
> the correct approach? (as I had to tweak the API a bit).
> 
> In particular the code does not detect interrupts and exception
> frames, and does not yet check whether the code address is valid.
> The latter check would also have to be omitted for the latest frame
> on other tasks' stacks. This would require some more tweaking.
> 
> unwind_frame() now reports whether we had to stop normally or due to
> an error condition; walk_stackframe() will pass that info.
> __save_stack_trace() is used for a start to check the validity of a
> frame; maybe save_stack_trace_tsk_reliable() will need its own callback.
> 
> Any comments welcome.
> 
> Signed-off-by: Torsten Duwe <duwe@suse.de>

Before we do this we'll need the same analysis we did for ppc64le to
figure out if objtool is needed.

-- 
Josh