[Bug 1212162] New: Exception handling corrupts a VLA

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1212162

Bug ID: 1212162
           Summary: Exception handling corrupts a VLA
           Product: Fedora
           Version: 21
         Component: mingw32-gcc
          Assignee: [e-mail]
          Reporter: [e-mail]
        QA Contact: [e-mail]
                CC: [e-mail],
                    [e-mail],
                    [e-mail], [e-mail]

Description of problem:
Code:
-----------------------------------------------------------------
#include <iostream>
#include <cstring>
#include <sstream>
#include <stdexcept>

using namespace std;

int main(int argc, char **argv)
{
        int n;
        stringstream ss(argv[1]);
        ss >> n;
        cout << "N: " << n << endl;
        char tbuff[n];
        try
        {
                memset(tbuff, 0, n);
                throw runtime_error("ERR");
        }
        catch (exception &e)
        {
                cout << "Writing to VLA" << endl;
                memset(tbuff, 0, n);
                cout << "Wrote" << endl;
        }
}
-----------------------------------------------------------------

Compiled with: 
/usr/bin/i686-w64-mingw32-g++ -O2  test.cpp -o t

Run with wine (similar results under Windows) results in crash:
[]% ./t 100                                         
fixme:winediag:start_process Wine Staging is a testing version containing
experimental patches.
fixme:winediag:start_process Please report bugs at http://bugs.wine-staging.com
(instead of winehq.org).
N: 100
Writing to VLA
wine: Unhandled page fault on read access to 0x00000000 at address (nil)
(thread 0009), starting debugger...
Unhandled exception: page fault on read access to 0x00000000 in 32-bit code
(0x00000000).
....

Version-Release number of selected component (if applicable):
mingw32-gcc-c++-4.9.2-1.fc21.x86_64

How reproducible:
100%

[Bug 1212162] Exception handling corrupts a VLA

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1212162

--- Comment #1 from Richard W.M. Jones  ---
I guess this is a bug in one of Wine, GCC, or mingw-w64.  But not
in Fedora packaging.  You'll get a faster response by taking the
bug report to one of those upstream projects.

[Bug 1212162] Exception handling corrupts a VLA

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1212162

Erik van Pienbroek  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]
          Component|mingw32-gcc                 |mingw-gcc
           Assignee|[e-mail]           |[e-mail]

--- Comment #2 from Erik van Pienbroek  ---
@Kai: any idea?

[Bug 1212162] Exception handling corrupts a VLA

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1212162

--- Comment #3 from Hedayat Vatankhah  ---
It is not wine, since the same crash happens on Windows for a similar code. It
should be either GCC (upstream GCC) or mingw (which is probably a branch of
upstream code?); but I don't know exactly where should I report bugs in
mingw-gcc, so I reported here (I thought there might be some Fedora specific
patches also). Anyway, the bug is probably related to MinGW sjlj exception
handling. If you think that I should report it upstream myself, please tell me
if I should report it in GCC bugzilla or Mingw64 one.

[Bug 1212162] Exception handling corrupts a VLA

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1212162

--- Comment #4 from Fedora End Of Life  ---
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Approximately 4 (four) weeks from now Fedora will stop maintaining
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bug reports from releases that are no longer maintained. At that time
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Although we aim to fix as many bugs as possible during every release's 
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[Bug 1212162] Exception handling corrupts a VLA

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1212162

Hedayat Vatankhah  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
    External Bug ID|                            |GNU Compiler Collection
                   |                            |68213
            Version|21                          |22