Hi Dave,

the reason why I went the gdbserver way is this:

Attaching to program:
/home/ksekera/vpp/build-root/install-vpp_lite_debug-native/vpp/bin/vpp,
process 7101
Could not attach to process.  If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user.  For more details, see
/etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.

I know this can be tuned, but I wanted it to be as user friendly as
possible. One might need to work on a machine where one doesn't have
sudo rights (like the aurora boxes).

I agree with the sucking part re gdb server, but so far it worked fine
for me. It's just a different line to copy-paste. The only drawback I
see with the gdbserver is the need to check for user stupidity in case
the user just hints enter blindly, while VPP is stuck in gdb server - but I've
added a warning for that case so that's done.

Do you know of any other reasons for not using gdb server?

Otherwise the flow is the same as you describe - wait for ENTER and run the
testcase.

Now that I think about it, we can have both, S=1 for server, G=1 for
just waiting for the user to attach the gdb if you want.

Maybe even give it more descriptive names?

Thanks,
Klement

On Fri, Oct 28, 2016 at 07:26:34PM +0200, Dave Barach (dbarach) wrote:
>    Dear Klement,
> 
>     
> 
>    Debugging w/ coredumps is just about worth supporting. I won't use it, but
>    someone else might. Personally, I'd forget it.
> 
>     
> 
>    Debugging w/ gdbserver is a total fail. No need to support it. Gdbserver
>    sucks.
> 
>     
> 
>    What I'm doing right now which is simple and effective: after starting
>    vpp, but before doing anything: print the vpp pid, and [in the cave-man
>    dbarach hack version] sleep for a while. In the non-caveman version, wait
>    until the user types "<return>".
> 
>     
> 
>    Meanwhile, in another window: start gdb + emacs on the vpp-lite
>    executable. Once the vpp pid is obvious: type "(gdb) attach <pid>". Set
>    breakpoints as desired, then type "continue".
> 
>     
> 
>    That's the slick / adult way to debug vpp.
> 
>     
> 
>    By the way, the L2BD test failure seems related to using the same mac
>    address on multiple interfaces. That’s prima facie illegal. Please don’t
>    do that.
> 
>     
> 
>    I see the code add these 4 raw keys to the l2 FIB:
> 
>     
> 
>    2: /x key0.raw = 0x101ff0000000001
> 
>    2: /x key0.raw = 0x201ff0000000001
> 
>    2: /x key0.raw = 0x301ff0000000001
> 
>    2: /x key0.raw = 0x401ff0000000001
> 
>     
> 
>    Take the mild assumption that these numbers hash to values which won’t
>    differ in low-order bits. Contestant #5 comes along, and runs the hash
>    table out of memory trying to pry these entries apart. I’ll go make sure
>    that I’m right - after lunch - but I’d STRONGLY suggest trying different
>    MAC addresses if you want the test to pass instantaneously...
> 
>     
> 
>    Thanks… Dave
> 
>     
> 
>    -----Original Message-----
>    From: Klement Sekera -X (ksekera - PANTHEON TECHNOLOGIES at Cisco)
>    Sent: Friday, October 28, 2016 12:47 PM
>    To: Dave Barach (dbarach) <dbar...@cisco.com>
>    Cc: Jan Gelety -X (jgelety - PANTHEON TECHNOLOGIES at Cisco)
>    <jgel...@cisco.com>; vpp-dev@lists.fd.io; csit-...@lists.fd.io
>    Subject: Re: [vpp-dev] L2BD test failing during MAC learning - VPP-518
> 
>     
> 
>    Hi Dave,
> 
>     
> 
>    2 options:
> 
>     
> 
>    1.) if you set ulimit -c properly and do a make test-debug I=1 TEST=l2bd
> 
>    (or just make test-debug I=1), the test framework should detect the
> 
>    core, fire up a gdb, load it and give you control (I stands for
> 
>    "interactive" here)
> 
>     
> 
>    2.) this one is not committed yet, but I have a patch which adds S=1 for
> 
>    running in gdbserver from the start - so at the beginning of each test
> 
>    case, it starts the vpp in gdbserver, prints the command line to attach
> 
>    gdb and waits for an <ENTER> so that you can set breakpoints etc.. I
> 
>    hope to push this to gerrit soon...
> 
>     
> 
>    Thanks,
> 
>    Klement
> 
>     
> 
>    On Fri, Oct 28, 2016 at 04:17:48PM +0000, Dave Barach (dbarach) wrote:
> 
>    > Dear Jan,
> 
>    >
> 
>    > This looks for all the world like a bounded-index extensible hash
>    jackpot. If that's so, the fix is obvious but it will take a bit of time
>    to code and test.
> 
>    >
> 
>    > Before I go there, I'll need to blow it up myself and poke around in
>    gdb. Have folks implemented the scheme I asked for - to pause test(s) so a
>    developer can attach to vpp from gdb - before anything else happens?
> 
>    >
> 
>    > If not, I can stick a sleep into the test BUT that feature request is
>    very important.
> 
>    >
> 
>    > Thanks... Dave
> 
>    >
> 
>    > From: [1]vpp-dev-boun...@lists.fd.io
>    [[2]mailto:vpp-dev-boun...@lists.fd.io] On Behalf Of Jan Gelety -X
>    (jgelety - PANTHEON TECHNOLOGIES at Cisco)
> 
>    > Sent: Friday, October 28, 2016 12:02 PM
> 
>    > To: [3]vpp-dev@lists.fd.io
> 
>    > Cc: [4]csit-...@lists.fd.io
> 
>    > Subject: [vpp-dev] L2BD test failing during MAC learning - VPP-518
> 
>    >
> 
>    > Dear vpp developers,
> 
>    >
> 
>    > We found out that VPP crashes during the MAC learning when run L2BD test
>    that is part of the test framework. The issue is reported here:
>    [5]https://jira.fd.io/browse/VPP-518
> 
>    >
> 
>    > Regards,
> 
>    > Jan
> 
>    >
> 
>     
> 
>    > _______________________________________________
> 
>    > vpp-dev mailing list
> 
>    > [6]vpp-dev@lists.fd.io
> 
>    > [7]https://lists.fd.io/mailman/listinfo/vpp-dev
> 
> References
> 
>    Visible links
>    1. mailto:vpp-dev-boun...@lists.fd.io
>    2. mailto:vpp-dev-boun...@lists.fd.io
>    3. mailto:vpp-dev@lists.fd.io
>    4. mailto:csit-...@lists.fd.io
>    5. https://jira.fd.io/browse/VPP-518
>    6. mailto:vpp-dev@lists.fd.io
>    7. https://lists.fd.io/mailman/listinfo/vpp-dev
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  • [vpp-dev] L2B... Jan Gelety -X (jgelety - PANTHEON TECHNOLOGIES at Cisco)
    • Re: [vpp... Dave Barach (dbarach)
      • Re: ... Dave Barach (dbarach)
      • Re: ... Klement Sekera -X (ksekera - PANTHEON TECHNOLOGIES at Cisco)
        • ... Dave Barach (dbarach)
          • ... Klement Sekera -X (ksekera - PANTHEON TECHNOLOGIES at Cisco)
            • ... John Lo (loj)
            • ... Dave Barach (dbarach)
              • ... Luke, Chris
              • ... Klement Sekera -X (ksekera - PANTHEON TECHNOLOGIES at Cisco)
                • ... Burt Silverman
                • ... Klement Sekera -X (ksekera - PANTHEON TECHNOLOGIES at Cisco)
    • Re: [vpp... Dave Barach (dbarach)

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