Ian,

You don't mention a platform so I will assume Linux.

GNU make 3.81 dates from 2006, and 3.82 was released in 2010. That's a lot
of bugfixes, so the first thing is to try at least 3.82 and ideally the CVS
version which has ~3 more years of fixes. Building the CVS versions is not
hard if you have a fairly modern system which either has or allows you to
add a couple of required packages (see the README.cvs file). I suggest
turning off any -O flags and adding -g; not only does this improve
debugging and stack dumps but there's a class of subtle bug which can be
triggered by optimization.

If you still see the problem with the CVS version (which identifies as
3.82.90 under --version) then you could try looking at what the process is
doing. The way I often start in situations like this is to "echo $$" in the
window where you plan to run make, to get what will be its parent pid. Then
run make, and in another window run something like "pstree -a -p -l <pid>"
with that parent pid you collected. This should clarify the process tree
situation; either make will be stuck internally (no new children) or will
be waiting on some subprocess which doesn't return. Though in this case it
seems fairly clear there are no new processes.

Assuming the hang is within make, you could try forcing a core dump. This
can be done with kill -BUS (or there may be a better way, Linux is not my
native country). Something else to try first would be "strace -p
<make-pid>". This may generate a lot of data but there may be a cycle which
provides a clue. Or make may just be sleeping, waiting for some resource,
in which case strace should help figure out what that resource is.

These may provide useful clues. However, based on the data you provided I'd
bet on a bug in make and your best hope is that it's been fixed in the last
~7 years.

David Boyce


On Mon, Jan 7, 2013 at 10:17 AM, Ian Lynagh <ig...@earth.li> wrote:

>
> Hi all,
>
> I've got a makefile for a large project which appears to send make into
> an infinite loop. I wonder if anyone could help me work out what is
> going wrong, and how to fix it, please?
>
> Unfortunately, it does so after about 30mins of compiling with parallel
> make (using e.g. -j5), and making a small testcase is unlikely to be
> easy.
>
> I've run make with the -d flag, and put the part of the log around where
> it starts to go wrong here:
>     http://lambda.haskell.org/~igloo/make-loop.txt
> (14MB).
>
> My understand is:
>
> * around line 1, there are 2 child processes building things, one
>   of which finishes
>
> * around line 2607, there is 1 child process building something, and
>   another child is started
>
> * around line 18477 there are 2 child processes building things, one
>   of which finishes
>
> * around line 36876 there is 1 process building something, and it
>   finishes
>
> * on line 55282 an iteration of the infinite loop starts
> * on line 73678 the next iteration of the infinite loop starts
> * on line 92074 the next iteration of the infinite loop starts
> * on line 110470 the next iteration of the infinite loop starts
> * on line 128866 the next iteration of the infinite loop starts
>
> The end of one loop and start of the next looks like this:
>
>     The prerequisites of `libraries/dist-haddock/index.html' are being
> made.
>    Finished prerequisites of target file `all_library_doc_index'.
>   The prerequisites of `all_library_doc_index' are being made.
>  Finished prerequisites of target file `all'.
> The prerequisites of `all' are being made.
> Considering target file `all'.
>  File `all' does not exist.
>   Considering target file `check_packages'.
>   File `check_packages' was considered already.
>   Considering target file `all_utils/mkdirhier'.
>
> Note that there are no "Live child" lines or anything.
>
> If I ^C it, and run make again, then compilation continues and succeeds.
>
> Is this a bug in make, or in my makefiles? If the former, is there a
> workaround? If the latter, have you got any advice on how to diagnose it
> please?
>
>
> I have "GNU Make 3.81".
>
>
> Thanks
> Ian
>
>
> _______________________________________________
> Bug-make mailing list
> Bug-make@gnu.org
> https://lists.gnu.org/mailman/listinfo/bug-make
>
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