Help needed to debug segfault when using ctypes

Hi,

In following patch I am using ctypes to load libgfapi(GlusterFS API) to 
get the Gluster volume statvfs information.
http://gerrit.ovirt.org/#/c/17822

I am getting *segfault* when I run
vdsClient 0 glusterVolumeSizeInfoGet volumeName=gv1

But I checked as below and it is working.

cd /usr/share/vdsm
     python
     >> from gluster import gfapi
     >> print gfapi.volumeStatvfs("gv1")
     posix.statvfs_result(f_bsize=4096L, f_frsize=4096L, 
f_blocks=25803070L, f_bfree=19130426L, f_bavail=17819706L, 
f_files=6553600L,     f_ffree=5855876L, f_favail=5855876L, f_flag=4096L, 
f_namemax=255L)

Please suggest how I can debug this issue.

--
Regards
Aravinda

I haven't worked much on using ctypes in python.. but did you try to 
look into the core to see where exactly the segfault is happening.. that 
might give some clues for further debug.

On 08/22/2013 05:53 PM, Aravinda wrote:
> Hi,
>
> In following patch I am using ctypes to load libgfapi(GlusterFS API) 
> to get the Gluster volume statvfs information.
> http://gerrit.ovirt.org/#/c/17822
>
> I am getting *segfault* when I run
> vdsClient 0 glusterVolumeSizeInfoGet volumeName=gv1
>
> But I checked as below and it is working.
> cd /usr/share/vdsm
> python
> >> from gluster import gfapi
> >> print gfapi.volumeStatvfs("gv1")
> posix.statvfs_result(f_bsize=4096L, f_frsize=4096L, 
>
> f_blocks=25803070L, f_bfree=19130426L, f_bavail=17819706L, 
> f_files=6553600L,     f_ffree=5855876L, f_favail=5855876L, 
> f_flag=4096L, f_namemax=255L)
>
> Please suggest how I can debug this issue.
>
> --
> Regards
> Aravinda
>
> vdsm-devel mailing list
> [e-mail]
> https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel

Maybe you should pass it with quotes -> vdsClient 0 glusterVolumeSizeInfoGet volumeName="gv1"
But probably that's not the issue,
Did you try to add prints in http://gerrit.ovirt.org/#/c/17822/5/client/vdsClientGluster.py to see where the segfault is raised exactly ?
still, if you prefer to debug step by step you can use any remote debuger (as pycharm) and in this case its easy, as it only one process and direct flow to step on.
You need to check the all flow and not only the last call (gfapi.volumeStatvfs("gv1"))
If you sure it raises inside the gfapi call with the same "gv1" as input, let me know and I'll investigate more

Yaniv Bronhaim

----- Original Message -----
> From: "Aravinda" 
> To: [e-mail]
> Sent: Thursday, August 22, 2013 3:23:34 PM
> Subject: [vdsm] Help needed to debug segfault when using ctypes
>
> Hi,
>
> In following patch I am using ctypes to load libgfapi(GlusterFS API) to get
> the Gluster volume statvfs information.
> http://gerrit.ovirt.org/#/c/17822
>
> I am getting segfault when I run
> vdsClient 0 glusterVolumeSizeInfoGet volumeName=gv1
>
> But I checked as below and it is working.
>
> cd /usr/share/vdsm
> python
> > > from gluster import gfapi
> > > print gfapi.volumeStatvfs("gv1")
>
> posix.statvfs_result(f_bsize=4096L, f_frsize=4096L, f_blocks=25803070L,
> f_bfree=19130426L, f_bavail=17819706L, f_files=6553600L, f_ffree=5855876L,
> f_favail=5855876L, f_flag=4096L, f_namemax=255L)
>
> Please suggest how I can debug this issue.
>
> --
> Regards
> Aravinda
>
> vdsm-devel mailing list
> [e-mail]
> https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel

On 08/27/2013 12:03 PM, Yaniv Bronheim wrote:
> Maybe you should pass it with quotes -> vdsClient 0 glusterVolumeSizeInfoGet volumeName="gv1"
> But probably that's not the issue,
> Did you try to add prints in http://gerrit.ovirt.org/#/c/17822/5/client/vdsClientGluster.py to see where the segfault is raised exactly ?

No issue with vdsClient, I executed vdsm verb as below and got the same 
error.
         import xmlrpclib
         proxy = xmlrpclib.ServerProxy("http://localhost:54321")
         proxy.glusterVolumeSizeInfoGet("gv1")
> still, if you prefer to debug step by step you can use any remote debuger (as pycharm) and in this case its easy, as it only one process and direct flow to step on.
> You need to check the all flow and not only the last call (gfapi.volumeStatvfs("gv1"))

gfapi.volumeStatvfs has all the code related to loading/using libgfapi. 
This func is added as supervdsm method using the decorator @makePublic, 
which is used in /vdsm/gluster/api.py 
(self.svdsmProxy.glusterVolumeStatvfs(volumeName))

Will try to debug using remote debugger. Thanks for the suggestions.

--
regards
Aravinda
> If you sure it raises inside the gfapi call with the same "gv1" as input, let me know and I'll investigate more
>
> Yaniv Bronhaim
>
> ----- Original Message -----
> > From: "Aravinda" 
> > To: [e-mail]
> > Sent: Thursday, August 22, 2013 3:23:34 PM
> > Subject: [vdsm] Help needed to debug segfault when using ctypes
> >
> > Hi,
> >
> > In following patch I am using ctypes to load libgfapi(GlusterFS API) to get
> > the Gluster volume statvfs information.
> > http://gerrit.ovirt.org/#/c/17822
> >
> > I am getting segfault when I run
> > vdsClient 0 glusterVolumeSizeInfoGet volumeName=gv1
> >
> > But I checked as below and it is working.
> >
> > cd /usr/share/vdsm
> > python
> > > > from gluster import gfapi
> > > > print gfapi.volumeStatvfs("gv1")
> >
> > posix.statvfs_result(f_bsize=4096L, f_frsize=4096L, f_blocks=25803070L,
> > f_bfree=19130426L, f_bavail=17819706L, f_files=6553600L, f_ffree=5855876L,
> > f_favail=5855876L, f_flag=4096L, f_namemax=255L)
> >
> > Please suggest how I can debug this issue.
> >
> > --
> > Regards
> > Aravinda
> >
> > vdsm-devel mailing list
> > [e-mail]
> > https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel

Can you share vdsm.log and supervdsm.log , maybe I can find there something about the exception..

Yaniv Bronhaim.

----- Original Message -----
> From: "Aravinda" 
> To: "Yaniv Bronheim" 
> Cc: [e-mail]
> Sent: Tuesday, August 27, 2013 12:29:40 PM
> Subject: Re: [vdsm] Help needed to debug segfault when using ctypes
>
> On 08/27/2013 12:03 PM, Yaniv Bronheim wrote:
> > Maybe you should pass it with quotes -> vdsClient 0
> > glusterVolumeSizeInfoGet volumeName="gv1"
> > But probably that's not the issue,
> > Did you try to add prints in
> > http://gerrit.ovirt.org/#/c/17822/5/client/vdsClientGluster.py to see
> > where the segfault is raised exactly ?
>
> No issue with vdsClient, I executed vdsm verb as below and got the same
> error.
>          import xmlrpclib
>          proxy = xmlrpclib.ServerProxy("http://localhost:54321")
>          proxy.glusterVolumeSizeInfoGet("gv1")
> > still, if you prefer to debug step by step you can use any remote debuger
> > (as pycharm) and in this case its easy, as it only one process and direct
> > flow to step on.
> > You need to check the all flow and not only the last call
> > (gfapi.volumeStatvfs("gv1"))
>
> gfapi.volumeStatvfs has all the code related to loading/using libgfapi.
> This func is added as supervdsm method using the decorator @makePublic,
> which is used in /vdsm/gluster/api.py
> (self.svdsmProxy.glusterVolumeStatvfs(volumeName))
>
> Will try to debug using remote debugger. Thanks for the suggestions.
>
> --
> regards
> Aravinda
> > If you sure it raises inside the gfapi call with the same "gv1" as input,
> > let me know and I'll investigate more
> >
> > Yaniv Bronhaim
> >
> > ----- Original Message -----
> > > From: "Aravinda" 
> > > To: [e-mail]
> > > Sent: Thursday, August 22, 2013 3:23:34 PM
> > > Subject: [vdsm] Help needed to debug segfault when using ctypes
> > >
> > > Hi,
> > >
> > > In following patch I am using ctypes to load libgfapi(GlusterFS API) to
> > > get
> > > the Gluster volume statvfs information.
> > > http://gerrit.ovirt.org/#/c/17822
> > >
> > > I am getting segfault when I run
> > > vdsClient 0 glusterVolumeSizeInfoGet volumeName=gv1
> > >
> > > But I checked as below and it is working.
> > >
> > > cd /usr/share/vdsm
> > > python
> > > > > from gluster import gfapi
> > > > > print gfapi.volumeStatvfs("gv1")
> > >
> > > posix.statvfs_result(f_bsize=4096L, f_frsize=4096L, f_blocks=25803070L,
> > > f_bfree=19130426L, f_bavail=17819706L, f_files=6553600L, f_ffree=5855876L,
> > > f_favail=5855876L, f_flag=4096L, f_namemax=255L)
> > >
> > > Please suggest how I can debug this issue.
> > >
> > > --
> > > Regards
> > > Aravinda
> > >
> > > vdsm-devel mailing list
> > > [e-mail]
> > > https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel