bugGNU Octave - Bugs: bug #39000, Can't override BLAS XERBLA handler...


bug #39000: Can't override BLAS XERBLA handler on Windows

Submitted by:  Clemens Buchacher <drizzd>
Submitted on:  Wed 15 May 2013 04:07:23 PM UTC  
Category: LibrariesSeverity: 4 - Important
Priority: 5 - NormalItem Group: Crash
Status: Patch SubmittedAssigned to: None
Originator Name: Clemens BuchacherOpen/Closed: Open
Release: devOperating System: Microsoft Windows

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Tue 30 Aug 2016 06:41:27 AM UTC, comment #21:

@Avinoam: just nasty because I find it tedious to criticize coding style, if the patch itself is good ;-) sorry a bit off topic

Kai Torben Ohlhus <siko1056>
Project Member
Mon 29 Aug 2016 07:38:39 PM UTC, comment #20:

@Kai: Thanks for your remarks (Why nasty?)

Actually, this patch does solve some other bug reports, like bug #46330, (test/bug-46330.tst can be tested on Windows too).

About the coding stile - I'll try to improve the patch. Thanks :-)

Avinoam Kalma <avinoam>
Project Member
Mon 29 Aug 2016 08:37:52 AM UTC, comment #19:

I have tested the patch of comment #18 on Linux without problems. Calls like in comment #17 result in a nice warning, like Matlab does.



But as said in comment #17, only one of many potential cases is fixed by this patch.

Another nasty remark is the code formatting. Please do not introduce multiple empty lines and lines with only white space characters. See http://wiki.octave.org/C%2B%2B_style_guide.

Kai Torben Ohlhus <siko1056>
Project Member
Mon 29 Aug 2016 04:23:39 AM UTC, comment #18:

Another patch included. Please review.

This patch calculates the matrix norm, and if it is Inf or NaN,
the result is set to zero, rcon is also set to zero, and a singular matrix warning is shown. I have used
octave::warn_singular_matrix (), but maybe another warning should be used.

(file #38375)

Avinoam Kalma <avinoam>
Project Member
Tue 23 Aug 2016 09:51:49 AM UTC, comment #17:

Checking the example

The error (and the crash after it) is produced in calling

(line 2130 in liboctave/array/dMatrix.cc).

A workaround can be something like:

Checking the matrix norm (like in http://hg.savannah.gnu.org/hgweb/octave/rev/bf5fbf347aaf), and avoiding calling dgelsd in case of problematic norn.
But this changeset does not set an error or warning, as it should.

Such modification should also apply to other *Matrix.cc files.

Avinoam Kalma <avinoam>
Project Member
Fri 29 Jul 2016 03:22:57 PM UTC, comment #16:

Unfortunately, not all BLAS libraries make it easy to override the default error handler even though that was the original intent of having xerbla...

I suppose we could fix this for our mxe-octave builds for openblas and the reference blas. But that doesn't solve the problem generally. To do that requires cooperation from the people who are writing and packaging BLAS libraries.

Also, as I understand it, XERBLA should only be invoked when a BLAS or LAPACK routine is called incorrectly and we really shouldn't be making calls with invalid parameters.

For the example in comment 13, isn't that just a variation of bug #46330? But even though that bug is closed, I don't think it is really fixed yet. I'll comment there as well.

John W. Eaton <jwe>
Project Administrator
Thu 05 Feb 2015 01:25:19 AM UTC, comment #15:

I just got a Windows VM set up, same segfault here.

Mike Miller <mtmiller>
Project Administrator
Thu 05 Feb 2015 01:16:43 AM UTC, comment #14:

The simpler test case

produces the error you cited

The Windows OS then catches the error and says that the application tried to read memory at 0x010 (clearly a segfault) and then the program exits.

Re-titling the bug to reflect the real issue of being unable to override the XERBLA handler on Windows.

Rik <rik5>
Project Administrator
Wed 04 Feb 2015 03:27:08 PM UTC, comment #13:

Yes, this particular test case looks solved.

However, you're not seeing the xerbla error message that's supposed to show up if this test case were still triggering the underlying problem.

I closed bug #36211 as a duplicate of this one. The simpler test case in that report still shows the xerbla message on Linux for me, what does

do for you on Windows? On Linux, it prints "On entry to DLASCL parameter number 4 had an illegal value" and then catches the error and returns to the Octave prompt. On Windows, last time I checked, this would cause Octave to abort, which is what this bug is really about.

Mike Miller <mtmiller>
Project Administrator
Wed 04 Feb 2015 04:15:30 AM UTC, comment #12:

@Mike: I used a very recent tip (2/3/15) and I don't experience any problem with the test data. I used the NSIS installer route and tried both reference BLAS and OpenBLAS. I think whatever gremlin was there has been excised. If you're fine with that level of testing you can close the report.

Rik <rik5>
Project Administrator
Wed 04 Feb 2015 01:53:23 AM UTC, comment #11:

@Mike: I have a Windows XP VM. I'll test tonight. Going through the MXE compile though is going to take 1-2 hours.

Rik <rik5>
Project Administrator
Fri 30 Jan 2015 04:06:00 PM UTC, comment #10:

Is the BLAS/LAPACK error handler still not being correctly overridden in the current MXE build? I was able to reproduce this a year ago, but I don't have my WinXP VM at the moment to test a current build.

Mike Miller <mtmiller>
Project Administrator
Sat 11 Jan 2014 08:27:02 PM UTC, comment #9:

I get the same error as the original report with an MXE build of 3.8.0 in a Windows XP VM.

Mike Miller <mtmiller>
Project Administrator
Sat 18 May 2013 08:25:07 AM UTC, comment #8:

The system is a Core i5-2540M @ 2.60 GHz with Windows 7 64-bit.

I have changed MXE to build gcc 4.8.0 as a cross-compiler, which includes gfortran. So that may also make a difference in terms of floating point arithmetic.

Clemens Buchacher <drizzd>
Fri 17 May 2013 03:17:56 PM UTC, comment #7:

I'm not able to reproduce the problem with the MXE build either.

I do see a message about the matrix being singular, but no error from lapack.

What hardware are you using? I'm running in a virtual box system with Windows 7 installed.

In any case, I guess we should fix the MXE build so that we can overrride XERBLA with our own version so that it doesn't exit.

John W. Eaton <jwe>
Project Administrator
Fri 17 May 2013 01:12:12 PM UTC, comment #6:

I also cannot reproduce on Linux with octave 3.7.3+, lapack 3.4.2.

Clemens Buchacher <drizzd>
Fri 17 May 2013 01:01:00 PM UTC, comment #5:

I did not modify the lapack version in my MXE build. The version is 3.4.2.

In SRC/dlasd8.f there is this code:

$ WORK( IWK2 ), INFO )

  • If the root finder fails, the computation is terminated.


And XERBLA seems to print the error message that I am getting. DLASD8 in turn gets called via functions such as zgelsd.

Clemens Buchacher <drizzd>
Wed 15 May 2013 10:17:23 PM UTC, comment #4:

I'm unable to duplicate the problem. Are you using the reference version fo lapack that is included in the MXE-octave build, or replacing it with some other version?

The version of DLASD4 that is used by my MXE-octave build does not appear to do any argument checking. So I don't see where that message is coming from.

Also, Octave doesn't call DLASD4 directly, so if there is an invalid call, it seems that it would be a bug in LAPACK.

John W. Eaton <jwe>
Project Administrator
Wed 15 May 2013 04:47:01 PM UTC, comment #3:

That's because you can't do it in Win32 (at least not in the way you do it under Linux/UNIX). The functions in the BLAS DLL will always resolve xerbla to the symbol present in the BLAS DLL (I believe this is done at link time, when the DLL is created).

Michael Goffioul <goffioul>
Project Member
Wed 15 May 2013 04:32:17 PM UTC, comment #2:

This sounds like the same symptom as bug #38575. The xerbla error handler in liboctave is not overriding the xerbla error handler in the BLAS/LAPACK libraries.

Mike Miller <mtmiller>
Project Administrator
Wed 15 May 2013 04:09:52 PM UTC, comment #1:

Just to be clear. This crashes Octave, closing the command line window or returning back the cmd shell.

Clemens Buchacher <drizzd>
Wed 15 May 2013 04:07:23 PM UTC, original submission:

With my MXE build of the development branch I get this crash with the attached file.

% crashme.m
xy = load('xy.txt');
x = xy.x;
y = xy.y;
z = x\y;

> crashme

warning: matrix singular to machine precision, rcond = 1.57068e-020

    • On entry to DLASD4 parameter number -1 had an illegal value


> size(xy.x)

ans =

350 350

> size(xy.y)

ans =

350 1

Does not happen with the 3.6.4 mingw build from the wiki:

> crashme

warning: matrix singular to machine precision, rcond = 8.43218e-021

Clemens Buchacher <drizzd>


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Attach File(s):

Attached Files
file #38375:  bug39000.patch added by avinoam (2kB - application/octet-stream)
file #28088:  xy.dat.tar.gz added by drizzd (12kB - application/x-gzip)


Depends on the following items: None found

   bug dependencies.


Carbon-Copy List
  • -unavailable- added by siko1056 (Posted a comment)
  • -unavailable- added by avinoam
  • -unavailable- added by avinoam (Posted a comment)
  • -unavailable- added by rik5 (Posted a comment)
  • -unavailable- added by jwe (Posted a comment)
  • -unavailable- added by goffioul (Posted a comment)
  • -unavailable- added by mtmiller (Posted a comment)
  • -unavailable- added by drizzd (Submitted the item)

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    Follow 14 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Mon 29 Aug 2016 04:23:39 AM UTCavinoamAttached File-=>Added bug39000.patch, #38375
      StatusConfirmed=>Patch Submitted
      Carbon-Copy-=>Added siko1056
    Sat 12 Sep 2015 09:54:22 PM UTCmtmillerDependencies-=>bugs #45484 is dependent
    Tue 01 Sep 2015 03:25:35 PM UTCrik5Dependencies-=>bugs #45849 is dependent
    Thu 05 Feb 2015 01:25:19 AM UTCmtmillerSeverity3 - Normal=>4 - Important
    Thu 05 Feb 2015 01:16:43 AM UTCrik5StatusFixed=>Confirmed
      Summarymldivide crashes with DLASD4 parameter error=>Can't override BLAS XERBLA handler on Windows
    Wed 04 Feb 2015 04:15:30 AM UTCrik5StatusConfirmed=>Fixed
    Fri 30 Jan 2015 04:04:18 PM UTCmtmillerDependencies-=>bugs #43610 is dependent
    Sat 11 Jan 2014 08:31:42 PM UTCmtmillerDependencies-=>bugs #36211 is dependent
    Sat 11 Jan 2014 08:27:02 PM UTCmtmillerCategoryNone=>Libraries
    Wed 15 May 2013 04:07:23 PM UTCdrizzdAttached File-=>Added xy.dat.tar.gz, #28088

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