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Re: no stack trace with 2.6.11 and gdb 6.3
On Mon, 13 Jun 2005 08:26:46 -0700
"H. J. Lu" <hjl@lucon.org> wrote:
> On Mon, Jun 13, 2005 at 10:16:29AM -0500, Rich Coe wrote:
> > On Fri, 10 Jun 2005 19:21:48 -0700
> > "H. J. Lu" <hjl@lucon.org> wrote:
> > > On Fri, Jun 10, 2005 at 08:51:13PM -0400, Daniel Jacobowitz wrote:
> > > >
> > > > No, I told you that I expected it to work in CVS. If it does not, then
> > > > someone needs to reproduce your problem using an unpatched GDB and
> > > > debug it. I do not have a Red Hat x86_64 system on which to reproduce
> > > > it, but I may be able to elsewhere - if I have time.
> > >
> > > Gdb should support vDSO on Linux 2.6.11/x86_64 with this patch:
> > >
> > > http://sources.redhat.com/ml/gdb/2005-06/msg00095.html
> > >
> > > If it doesn't work, I will be interested to know.
> > > H.J.
> >
> > The patch makes it work only if you start the program from the gdb
> > command line. As I said in my original post:
>
> You are saying:
>
> 1. # gdb foo
> works.
>
> 2. But
> # foo
# foo &
> # gdb foo pid
> doesn't work?
Yes.
> Tell me how to reproduce it. I will take a look.
>
Compile the following program, -m32.
run it in the background, and attach with gdb.
get a bt.
Results:
gdb gtest 29769
GNU gdb Red Hat Linux (6.3.0.0-1.10rh)
Copyright 2004 Free Software Foundation, Inc.
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Type "show copying" to see the conditions.
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This GDB was configured as "x86_64-redhat-linux-gnu"...Using host libthread_db library "/lib64/tls/libthread_db.so.1".
Attaching to program: /data/rhcoe/data/mr/gtest, process 29769
Reading symbols from /lib/tls/libc.so.6...done.
Loaded symbols for /lib/tls/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
0xffffe405 in ?? ()
(gdb) bt
#0 0xffffe405 in ?? ()
#1 0xffffd9f8 in ?? ()
#2 0x4ba3e45d in ___newselect_nocancel () from /lib/tls/libc.so.6
#3 0x080484fe in myselect ()
#4 0x00000000 in ?? ()
(gdb) add-symbol-file-from-memory 0xffffe000
Reading symbols from shared object read from target memory...done.
(gdb) bt
#0 0xffffe405 in __kernel_vsyscall ()
#1 0x4ba3e45d in ___newselect_nocancel () from /lib/tls/libc.so.6
#2 0x080484fe in myselect ()
#3 0x08048565 in func_two ()
#4 0x0804858e in func_one ()
#5 0x080485cf in main ()
--
Rich Coe richard.coe@med.ge.com
General Electric Healthcare Technologies
Global Software Platforms, Computer Technology Team