From: Mark Brown <broonie@kernel.org>
To: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
jpoimboe@redhat.com, ardb@kernel.org, nobuta.keiya@fujitsu.com,
sjitindarsingh@gmail.com, catalin.marinas@arm.com,
will@kernel.org, jmorris@namei.org, pasha.tatashin@soleen.com,
jthierry@redhat.com, linux-arm-kernel@lists.infradead.org,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v6 3/3] arm64: Create a list of SYM_CODE functions, check return PC against list
Date: Thu, 29 Jul 2021 15:52:10 +0100 [thread overview]
Message-ID: <20210729145210.GP4670@sirena.org.uk> (raw)
In-Reply-To: <f9931a57-7a81-867b-fa2a-499d441c5acd@linux.microsoft.com>
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On Thu, Jul 29, 2021 at 09:06:26AM -0500, Madhavan T. Venkataraman wrote:
> On 7/28/21 12:25 PM, Mark Rutland wrote:
> > On Wed, Jun 30, 2021 at 05:33:56PM -0500, madvenka@linux.microsoft.com wrote:
> > Since some of the above is speculative (e.g. the bit about optprobes),
> > and as code will change over time, I think we should have a much terser
> > comment, e.g.
> > /*
> > * As SYM_CODE functions don't follow the usual calling
> > * conventions, we assume by default that any SYM_CODE function
> > * cannot be unwound reliably.
> > *
> > * Note that this includes exception entry/return sequences and
> > * trampoline for ftrace and kprobes.
> > */
> Just to confirm, are you suggesting that I remove the entire large comment
> detailing the various cases and replace the whole thing with the terse comment?
> I did the large comment because of Mark Brown's input that we must be verbose
> about all the cases so that it is clear in the future what the different
> cases are and how we handle them in this code. As the code evolves, the comments
> would evolve.
I do agree with Mark that this has probably gone from one extreme to the
other and could be cut back a lot - originally it didn't reference there
being complicated cases like the trampoline at all IIRC so you needed
external knowledge to figure out that those cases were handled.
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next prev parent reply other threads:[~2021-07-29 14:52 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3f2aab69a35c243c5e97f47c4ad84046355f5b90>
2021-06-30 22:33 ` [RFC PATCH v6 0/3] arm64: Implement stack trace reliability checks madvenka
2021-06-30 22:33 ` [RFC PATCH v6 1/3] arm64: Improve the unwinder return value madvenka
2021-07-28 16:56 ` Mark Rutland
2021-07-29 13:54 ` Madhavan T. Venkataraman
2021-06-30 22:33 ` [RFC PATCH v6 2/3] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-06-30 22:33 ` [RFC PATCH v6 3/3] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2021-07-28 17:25 ` Mark Rutland
2021-07-29 14:06 ` Madhavan T. Venkataraman
2021-07-29 14:52 ` Mark Brown [this message]
2021-07-29 17:07 ` Madhavan T. Venkataraman
2021-07-29 15:48 ` Mark Rutland
2021-07-29 16:27 ` Mark Brown
2021-07-29 17:09 ` Madhavan T. Venkataraman
2021-07-26 13:49 ` [RFC PATCH v6 0/3] arm64: Implement stack trace reliability checks Madhavan T. Venkataraman
2021-08-12 13:24 ` [RFC PATCH v7 0/4] arm64: Reorganize the unwinder and implement " madvenka
2021-08-12 13:24 ` [RFC PATCH v7 1/4] arm64: Make all stack walking functions use arch_stack_walk() madvenka
2021-08-12 15:23 ` Mark Brown
2021-08-12 16:30 ` Madhavan T. Venkataraman
2021-08-12 13:24 ` [RFC PATCH v7 2/4] arm64: Reorganize the unwinder code for better consistency and maintenance madvenka
2021-08-12 13:24 ` [RFC PATCH v7 3/4] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-08-12 13:24 ` [RFC PATCH v7 4/4] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2021-08-12 18:31 ` [RFC PATCH v7 0/4] arm64: Reorganize the unwinder and implement stack trace reliability checks Madhavan T. Venkataraman
2021-08-12 18:45 ` Madhavan T. Venkataraman
2021-08-12 18:35 ` madvenka
2021-08-12 18:35 ` [RFC PATCH v7 1/4] arm64: Make all stack walking functions use arch_stack_walk() madvenka
2021-08-12 18:35 ` [RFC PATCH v7 2/4] arm64: Reorganize the unwinder code for better consistency and maintenance madvenka
2021-08-12 18:35 ` [RFC PATCH v7 3/4] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-08-12 18:35 ` [RFC PATCH v7 4/4] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
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