Itanium and GDB on 2.6.x kernels with pthreads

[David Lecomber <david@allinea.com>]

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Dear all,

Attached is a simple program, and simple script for GDB (current CVS,
and previous versions)

gcc -o pf -g pf.c -lm -lpthread

gdb ./pf < gdb.script

The script is a break main and then 'next' four times, followed by quit.

On a 2.4.21 Itanium system, it's quick and quits happily.

On a 2.6.5 Itanium, it hangs during the later nexts.  Does anyone have a
more recent Itanium they could try and see if this is a transient kernel
issue?  

Note, the Intel IDB debugger does not have a problem with this test
case.

GDB consumes CPU, and a 'strace' shows it to be doing repeatedly:

wait4(29113, 0x60000fffffffa730, 0, NULL) = -1 ECHILD (No child
processes)
wait4(29113, [{WIFSTOPPED(s) && WSTOPSIG(s) == SIGTRAP}], __WCLONE,
NULL) = 29113
ptrace(PTRACE_CONT, 29113, 0, SIG_0)    = 0
wait4(29113, 0x60000fffffffa730, 0, NULL) = -1 ECHILD (No child
processes)


Also, just generally, signal processing is goofed up -- and if I try to
attach to the running GDB I just see:

Loaded symbols for /lib/tls/libthread_db.so.1
<signal handler called>
(gdb) bt
#0  <signal handler called>
Cannot access memory at address 0x28
(gdb) The program is running.  Quit anyway (and detach it)? (y or n) y


Anyone seen this before?  If someone could verify this is ok on their
system, I'd appreciate it..

d.


-- 
David Lecomber <david@allinea.com>

[-- Attachment #2: pf.c --]
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#include <pthread.h>
#include <math.h>
#include <stdio.h>

void f(char* s)
{
  int i;
  printf("Hello from : %s\n", s);
  fflush(stdout);
  for (i = 0 ; i < 100000000; i++)
    {
      float f = sqrt(i);
    }
  printf("Goodbye from : %s\n", s);
  fflush(stdout);
}

int main()
{
  pthread_t t1;
  pthread_t t2;

  pthread_create(&t1, NULL, (void*) &f, "One");
  pthread_create(&t2, NULL, (void*) &f, "Two");

  pthread_join(t1, NULL);
  pthread_join(t2, NULL);

}

[-- Attachment #3: gdb.script --]
[-- Type: text/plain, Size: 32 bytes --]

b main
run 
next
next
next
quit