Re: t9128 failing randomly with svn 1.9?

From: Eric Wong <e@80x24.org>
Date: Jan 29, 2018, 12:06 UTC
Message-ID: <20180129120627.al2xvx4yhhvwn6ih@untitled>
In-Reply-To: <20180129025812.GD1427@zaya.teonanacatl.net>

Todd Zullinger <tmz@pobox.com> wrote:

Show 10 quoted lines

> brian m. carlson wrote:
> > r7 = f8467f2cee3bcead03e84cb51cf44f467a87457d (refs/remotes/origin/tags/tag3)
> > error: git-svn died of signal 11
> > 
> > Doing the following three times, I had two crashes.
> > 
> > (set -e; for i in $(seq 1 20); do (cd t && ./t9128-git-svn-cmd-branch.sh --verbose); done)
> > 
> > I'm not really familiar with git svn or its internals, and I didn't see
> > anything recently on the list about this.  Is this issue known?

The SVN bindings have been known to crash occasionally and I can't really get my head around XS/Swig or Perl internals :/ Looking at the coredump, it seems to be around exit and destruction (only Perl in the stacktrace, nothing from libsvn). So I suspect it's a lifetime or ordering bug, testing a patch below (slowly).

"branch" is also the only place we use SVN::Client->new these days.

Show 10 quoted lines

> For me, it's tests 3 and 4 which fail with the same error.
> I thought it was a failure in subversion or the perl
> bindings rather than git, so I simply disabled them in the
> Fedora builds.  The Debian packages skip 9128 as well (and
> 9167, which fails similarly).
> 
> I've seen the failures in t9141 from 'git svn branch' as
> well.  I made a note to re-enable those tests after Jeff's
> work to make it easier to run with shell tracing enabled by
> default, but have not done so yet.

Just a guess, but it might be related to destruction order. Running t9128 on a 32-bit Pentium-M, it took me 39 tries to fail.

diff --git a/git-svn.perl b/git-svn.perl
index 76a75d0b3d..2ba14269bb 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -1200,6 +1200,11 @@ sub cmd_branch {
 	$ctx->copy($src, $rev, $dst)
 		unless $_dry_run;
 
+	# Release resources held by ctx before creating another SVN::Ra
+	# so destruction is orderly.  This seems necessary Subversion 1.9.5
+	# to avoid segfaults.
+	$ctx = undef;
+
 	$gs->fetch_all;
 }
 

I'll be looping t9128, t9141 and t9167 with that for a few
hours or day.  Will report back sooner if it fails.
I'm on an ancient 32-bit system, I guess you guys encountered
it on 64-bit machines?