[Bug gdb/15093] New: gdb cannot follow cross-arch execve from x86_64 to i386

[Bug gdb/15093] New: gdb cannot follow cross-arch execve from x86_64 to i386

[reid.kleckner at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15093

             Bug #: 15093
           Summary: gdb cannot follow cross-arch execve from x86_64 to
                    i386
           Product: gdb
           Version: 7.5
            Status: NEW
          Severity: normal
          Priority: P2
         Component: gdb
        AssignedTo: unassigned@sourceware.org
        ReportedBy: reid.kleckner@gmail.com
    Classification: Unclassified


This doesn't work for me on my system:

$ cat hello.c
#include <stdio.h>
int main(void) {
    printf("hello, world!\n");
    return 0;
}

$ gcc -m32 hello.c -o hello

$ ./hello
hello, world!

$ gdb --args /bin/bash -norc -c ./hello
...
(gdb) run
Starting program: /bin/bash -norc -c ./hello
process 25845 is executing new program:
/usr/local/google/home/rnk/dynamorio/build/hello
warning: Selected architecture i386 is not compatible with reported target
architecture i386:x86-64
Architecture of file not recognized.
(gdb) 

>From then on I can't debug hello.  It keeps pretending it's a 64-bit process.

I can easily debug ./hello directly with this version of gdb, so I don't see
why it can't follow the execve.  I tried various things like set arch i386 and
file ./hello, but it doesn't get gdb to do the right thing.

Is this supposed to work?  I'm not sure if what I'm asking for is a bug report
or a feature request.

This is using Google's patched version of gdb:
$ gdb --version
GNU gdb (GDB) 7.5-gg7

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[Bug gdb/15093] gdb cannot follow cross-arch execve from x86_64 to i386

[reid.kleckner at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15093

--- Comment #1 from Reid Kleckner <reid.kleckner at gmail dot com> 2013-02-02 17:08:43 UTC ---
I should mention bash is x86_64 here.

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[Bug gdb/15093] gdb cannot follow cross-arch execve from x86_64 to i386

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15093

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |WAITING
                 CC|                            |tromey at redhat dot com

--- Comment #2 from Tom Tromey <tromey at redhat dot com> 2013-02-04 17:47:44 UTC ---
(In reply to comment #0)

> This is using Google's patched version of gdb:
> $ gdb --version
> GNU gdb (GDB) 7.5-gg7

I don't know what is in this gdb.

I think this looks like PR 14306.
Could you see if that fix is in your tree?
Or if building a newer gdb fixes the problem?

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[Bug gdb/15093] gdb cannot follow cross-arch execve from x86_64 to i386

[reid.kleckner at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15093

Reid Kleckner <reid.kleckner at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |DUPLICATE

--- Comment #3 from Reid Kleckner <reid.kleckner at gmail dot com> 2013-02-04 18:17:17 UTC ---
Ah, great, it's a dupe.  A more recent gdb works fine.  Thanks!

*** This bug has been marked as a duplicate of bug 14306 ***

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