Mailing List Archive

R: Xen 4.4.2, coverage does not work properly (zithro)
Hello zithro,

thanks for the fast reply. I tried using xencov reset, I also tried to install Xen 4.4.4 on Debian 8 (Jessie) and Xen 4.7.6 on Ubuntu 16.04 but unfortunately I had the same problem with the xencov read.

I too am afraid that the coverage support on the older versions is slightly buggy.

Thank you for the guide you linked, that one is a reference for the new versions. I also have a machine with Xen 4.16 where the coverage support works fine.

Unfortunately, there are no Kconfig files with the CONFIG_COVERAGE option in the old versions. The older versions used a macro called TEST_COVERAGE that had the same purpose but was a little different.

I will continue to look for patches in hopes of solving it.

Da: xen-users-request@lists.xenproject.org<mailto:xen-users-request@lists.xenproject.org>
Inviato: venerd? 5 maggio 2023 14:01
A: xen-users@lists.xenproject.org<mailto:xen-users@lists.xenproject.org>
Oggetto: Xen-users Digest, Vol 219, Issue 3

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Today's Topics:

1. Re: Xen 4.4.2, coverage does not work properly (zithro)


----------------------------------------------------------------------

Message: 1
Date: Thu, 4 May 2023 23:39:25 +0200
From: zithro <slack@rabbit.lu>
To: xen-users@lists.xenproject.org
Subject: Re: Xen 4.4.2, coverage does not work properly
Message-ID: <2005246c-531c-d207-a293-05d04b75cefe@rabbit.lu>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 02 May 2023 14:23, Giuseppe De Rosa wrote:
> Hello everybody,
>
> I apologize for asking for help on such an outdated version of Xen. I would like to understand why xencov read always returns the same dat file as shown in the attached file.
>
> I followed this guide https://wiki.xenproject.org/index.php?title=Compiling_Xen_From_Source&oldid=17237 (14 September 2016 version) to compile Xen from source and this guide to enable coverage support https://xenbits.xen.org/docs/4.8-testing/misc/coverage.html. I also applied this patch https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg03353.html because I had some compilation errors.
>
> Everything went fine until I used xencov read. The result is always the same (4 bytes returned, always .CTX) but the file is malformed because xencov_split cannot read that.
>
> I am using Ubuntu 14.04. I made sure to enable test coverage support under xen/Config.mk and gcov under tools/qemu-xen/configure. I checked the compilation logs and every file was instrumented with the -ftest-coverage option.
>
>

Maybe look for more 4.4 bug reports about coverage, as another patch is
needed ?
I found that they almost totally rewrote coverage in 4.7.

The current man page about coverage
(https://xenbits.xen.org/docs/unstable/hypervisor-guide/code-coverage.html)
is a bit different.
"enable CONFIG_COVERAGE in Kconfig".
(mentionned in
"https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg03363.html").
There's also "xencov reset".

But honestly this is above me. Maybe try the xen-devel ML ?

PS: at first I thought your post was a prank, but no, just discovered
"xl li == xl lis == xl list" ! Why not "xl l" though ^^



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Re: R: Xen 4.4.2, coverage does not work properly (zithro) [ In reply to ]
On 05 May 2023 15:50, Giuseppe De Rosa wrote:
> Hello zithro,
Hello,

> I will continue to look for patches in hopes of solving it.
Good luck

Also, I found a topic in xen-devel (by an italian too ^^) : "Crash when
using xencov" from 27 june 2022, user "Carmine Cesarano
<c.cesarano@hotmail.it>"

>
> Da: xen-users-request@lists.xenproject.org<mailto:xen-users-request@lists.xenproject.org>
> Inviato: venerdì 5 maggio 2023 14:01
> A: xen-users@lists.xenproject.org<mailto:xen-users@lists.xenproject.org>
> Oggetto: Xen-users Digest, Vol 219, Issue 3
[snipped]
> Today's Topics:
> 1. Re: Xen 4.4.2, coverage does not work properly (zithro)
[snipped]

Just a few *friendly* remarks:
- when posting or replying to Mailing Lists in general (not only this
one), only reply to the answer you got (in this case, my reply). *Do not
reply to a digest* or whatever else, it breaks the flow and is harder to
read for actual and future readers, and consumes bandwidth for nothing.
- *Avoid top-posting*, rather reply below the answer you got, or if
needed in between (like I did above with hello and good luck). As an
example, funny quote :
[quote]
- Because it messes up the order in which people normally read text.
- Why is top-posting such a bad thing?
- Top-posting.
- What is the most annoying thing in e-mail?
[/quote]

Happy debugging !