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Re: [PATCH 7/7] gnttab: unreachable code when GNTTAB_MAX_VERSION < 2
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
- Date: Tue, 28 Jul 2026 17:53:52 +0200
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- Delivery-date: Tue, 28 Jul 2026 15:53:55 +0000
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On 2026-07-28 17:42, Jan Beulich wrote:
On 28.07.2026 17:40, Nicola Vetrini wrote:
On 2026-07-28 15:53, Jan Beulich wrote:
I'm surprised Eclair doesn't spot the large chunks of unreachable
code
on
Arm, i.e. violations of Misra C:2012 rule 2.1.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
This pretty certainly isn't dealing with everything. For example,
with
another helper the gt_version field could likely also become
conditional.
With some more effort the nr_status_frames field similarly could
become
conditional.
[...]
Hard to judge only looking at the diff. Is this code unreachable in
the
arm64-allcode analysis configuration as well?
Arm uniformly has
#define GNTTAB_MAX_VERSION 1
so all gnttab-v2 code is unreachable there, no matter what
configuration.
Jan
I see. Existing deviations may play a role here in excluding caution
reports that would otherwise be generated, particularly
-config=MC3A2.R2.1,+reports={safe,"first_area(^.*has an
invariantly.*$)"}
I see only one condition "GNTTAB_MAX_VERSION" is used directly, while
the others are via "opt_gnttab_max_version" which is why I reasoned
there might be cautions involved, instead of violations.
--
Nicola Vetrini, B.Sc.
Software Engineer
BUGSENG (https://bugseng.com)
LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253
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