Re: Building packages with buildd and qemu-kvm

[Samuel Thibault]

Svante Signell, le Wed 13 Apr 2011 11:28:34 +0200, a écrit :
> On Wed, 2011-04-13 at 11:10 +0200, Samuel Thibault wrote:
> > Svante Signell, le Wed 13 Apr 2011 11:05:30 +0200, a écrit :
> > > On Wed, 2011-04-13 at 10:43 +0200, Samuel Thibault wrote:
> > > > Svante Signell, le Wed 13 Apr 2011 07:46:54 +0200, a écrit :
> > > > > make[1]: *** [lapack_testing] Error 141
> > > > > 
> > > > > Both tests end with a signal being sent for a kill from fakeroot in 
> > > > > the
> > > > > first case and in libfakreoot during a read operation. Both had happen
> > > > > during redirection of stdin and stdout. Why issuing a kill in the
> > > > > middle of execution? Are these functions also handled by libpipe? If
> > > > 
> > > > 141 is 128 + 13, i.e. SIGPIPE. This is supposed to happen when the
> > > > reader part of a pipe has disappeared while the writer was trying to
> > > > write to the pipe. It's not supposed to happen on the reader part.
> > > 
> > > How to interpret your answer, is there a problem with libpipe or not?
> > 
> > Err, yes. "It's not supposed to happen" => there's a bug. Since it's on
> > a pipe, it's most probably on pflocal or libpipe. glibc could be at
> > stake, but I doubt it, since it doesn't do anything different for files
> > or for pipes.
> 
> How to best debug libpipe, setting breakpoints in Ggdb?

There is no universal way to debug anything. First look for SIGPIPE /
EPIPE in the source code to get a crasp at where that happens. Possibly
simply put printfs to know what the values are when this happens (which
is more tenable than debugging with gdb, since you'll also be debugging
all pipes in the system).

> libfakeroot: read: Connection reset by peer

Also, you should probably check how things work when not using fakeroot,
i.e. when the build already runs as root. Maybe libfakeroot has bugs
here too (we do know that is has some bugs, see the race condition in
the debian bts).

> make[1]: *** [lapack_testing] Error 141
> make[1]: Leaving directory `/home/srs/DEBs/lapack/lapack-3.3.0'
> make: *** [testing/xeigtsts] Error 2
> /usr/bin/fakeroot: line 1: kill: (21461) - No such process
> dpkg-buildpackage: error: fakeroot debian/rules binary gave error exit
> status 2
> 
> > When you see no progress from the build, check out the last
> > started process and what they are doing.
> 
> I get output all the time until the crash.

Ok. You may want to simply drop the timeout just to be on the safe side.

Samuel