Date: Tue, 11 Feb 2003 19:09:13 +0000 From: Peter Edwards <peter.edwards@openet-telecom.com> To: FreeBSD-gnats-submit@FreeBSD.org Subject: gnu/48183: [patch] gdb on a corefile from a threaded process can't see Message-ID: <20030211190913.247272d3.peter.edwards@openet-telecom.com>
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>Number: 48183
>Category: gnu
>Synopsis: [patch] gdb on a corefile from a threaded process can't see
>Confidential: no
>Severity: serious
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Feb 11 11:10:09 PST 2003
>Closed-Date:
>Last-Modified:
>Originator: Peter Edwards
>Release: FreeBSD 5.0-CURRENT i386
>Organization:
>Environment:
System: FreeBSD rocklobster 5.0-CURRENT FreeBSD 5.0-CURRENT #4: Tue Feb 11
09:17:38 GMT 2003
petere@archie:/pub/FreeBSD/obj/pub/FreeBSD/current/src/sys/ROCKLOBSTER
i386
>Description:
This was originally posted to -current in
<20030207124244.74bf9df7.peter.edwards@openet-telecom.com>
I figured i'd record it here so it's not forgotten.
gdb doesn't find threads in corefiles: The support was just missing.
Attached is a patch, sample program, and gdb output when running it.
>How-To-Repeat:
Compile this:
=09
#include <sys/types.h>
#include <signal.h>
#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <err.h>
void *thr(void *a)
{
printf("started thread %d\n", (int)a);
pause();
return 0;
}
int main(int argc, char **argv)
{
const int THREADCOUNT =3D 4;
int i;
pthread_t threads[THREADCOUNT];
for (i =3D 0; i < THREADCOUNT; i++)
if (pthread_create(&threads[i], 0, thr, (void *)i) !=3D 0)
errx(-1, "cannot create thread");
sleep(1);
kill(0, SIGBUS);
return 0;
}
like this:
petere@rocklobster$ cc -o threadcore -Wall -g -pthread threadcore.c
then do this:
petere@rocklobster$ ./threadcore
started thread 0
started thread 1
started thread 2
started thread 3
zsh: bus error (core dumped) ./threadcore
petere@rocklobster$ gdb threadcore threadcore.core
GNU gdb 5.2.1 (FreeBSD)
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are welcome to change it and/or distribute copies of it under certain
conditions. Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for
details. This GDB was configured as "i386-undermydesk-freebsd"...
Core was generated by `threadcore'.
Program terminated with signal 10, Bus error.
Reading symbols from /usr/lib/libc_r.so.5...done.
Loaded symbols for /usr/lib/libc_r.so.5
Reading symbols from /usr/lib/libc.so.5...done.
Loaded symbols for /usr/lib/libc.so.5
Reading symbols from /usr/libexec/ld-elf.so.1...done.
Loaded symbols for /usr/libexec/ld-elf.so.1
#0 0x280d5463 in kill () from /usr/lib/libc.so.5
(gdb) i thr
* 1 process 41359 0x280d5463 in kill () from /usr/lib/libc.so.5
(gdb) quit
After applying the patch, try this:
petere@rocklobster$ /usr/src/gnu/usr.bin/binutils/gdb/gdb threadcore
threadcore.core GNU gdb 5.2.1 (FreeBSD)
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are welcome to change it and/or distribute copies of it under certain
conditions. Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for
details. This GDB was configured as "i386-undermydesk-freebsd"...
Core was generated by `threadcore'.
Program terminated with signal 10, Bus error.
Reading symbols from /usr/lib/libc_r.so.5...done.
Loaded symbols for /usr/lib/libc_r.so.5
Reading symbols from /usr/lib/libc.so.5...done.
Loaded symbols for /usr/lib/libc.so.5
Reading symbols from /usr/libexec/ld-elf.so.1...done.
Loaded symbols for /usr/libexec/ld-elf.so.1
#0 0x280d5463 in kill () from /usr/lib/libc.so.5
(gdb) i thr
7 Process 41359 0x280d5463 in kill () from /usr/lib/libc.so.5
6 Process 41359 0x2807b7ec in _thread_kern_sched () from
/usr/lib/libc_r.so.5
5 Process 41359 0x2807b7ec in _thread_kern_sched () from
/usr/lib/libc_r.so.5
4 Process 41359 0x2807b7ec in _thread_kern_sched () from
/usr/lib/libc_r.so.5
3 Process 41359 0x2807b7ec in _thread_kern_sched () from
/usr/lib/libc_r.so.5
2 Process 41359 0x2807b7ec in _thread_kern_sched () from
/usr/lib/libc_r.so.5
* 1 Process 41359 0x280d5463 in kill () from /usr/lib/libc.so.5
(gdb)=20
Enjoy,
Peter.
>Fix:
Index: freebsd-uthread.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file:
/pub/FreeBSD/development/FreeBSD-CVS/src/gnu/usr.bin/binutils/gdb/freebsd
-uthread.c,v
retrieving revision 1.10
diff -u -r1.10 freebsd-uthread.c
--- freebsd-uthread.c 4 Jan 2003 17:35:54 -0000 1.10
+++ freebsd-uthread.c 7 Feb 2003 12:34:19 -0000
@@ -46,6 +46,10 @@
#include <sys/stat.h>
#include "gdbcore.h"
=20
+int coreops_suppress_target =3D 1; /* Ugh. Override the version in
corelow.c. */
+extern struct target_ops core_ops; /* target vector for corelow.c */
+static struct target_ops orig_core_ops; /* target vector for corelow.c */
+
extern int child_suppress_run;
extern struct target_ops child_ops; /* target vector for inftarg.c */
=20
@@ -60,6 +64,7 @@
=20
/* Pointer to the next function on the objfile event chain. */
static void (*target_new_objfile_chain) (struct objfile *objfile);
+static void freebsd_uthread_find_new_threads (void);
=20
static void freebsd_uthread_resume PARAMS ((ptid_t pid, int step,
enum target_signal signo));
@@ -472,7 +477,10 @@
=20
if (freebsd_uthread_attaching || TIDGET(inferior_ptid) =3D=3D 0)
{
- child_ops.to_fetch_registers (regno);
+ if (target_has_execution)
+ child_ops.to_fetch_registers (regno);
+ else
+ orig_core_ops.to_fetch_registers (regno);
return;
}
=20
@@ -481,7 +489,10 @@
=20
if (active)
{
- child_ops.to_fetch_registers (regno);
+ if (target_has_execution)
+ child_ops.to_fetch_registers (regno);
+ else
+ orig_core_ops.to_fetch_registers (regno);
return;
}
=20
@@ -501,8 +512,12 @@
=20
for (regno =3D first_regno; regno <=3D last_regno; regno++)
{
- if (regmap[regno] =3D=3D -1)
- child_ops.to_fetch_registers (regno);
+ if (regmap[regno] =3D=3D -1) {
+ if (target_has_execution)
+ child_ops.to_fetch_registers (regno);
+ else
+ orig_core_ops.to_fetch_registers (regno);
+ }
else
if (thread)
supply_register (regno, (char*) ®base[regmap[regno]]);
@@ -683,6 +698,11 @@
LOOKUP_VALUE(PS_RUNNING);
LOOKUP_VALUE(PS_DEAD);
=20
+ if (!target_has_execution) {
+ read_thread_offsets();
+ freebsd_uthread_find_new_threads();
+ }
+
freebsd_uthread_active =3D 1;
}
=20
@@ -731,6 +751,27 @@
return ret;
}
=20
+static int
+freebsd_utcore_thread_alive (ptid_t ptid)
+{
+ return 1;
+}
+
+static void
+freebsd_utcore_attach (char *args, int from_tty)
+{
+ orig_core_ops.to_attach (args, from_tty);
+ push_target (&core_ops);
+ freebsd_uthread_attaching =3D 1;
+}
+
+static void
+freebsd_utcore_detach (char *args, int from_tty)
+{
+ unpush_target (&core_ops);
+ orig_core_ops.to_detach (args, from_tty);
+}
+
static void
freebsd_uthread_stop (void)
{
@@ -874,12 +915,41 @@
freebsd_uthread_vec.get_thread_info =3D freebsd_uthread_get_thread_info;
#endif
}
+=0C
+
+
+static void
+init_freebsd_core_ops ()
+{
+ orig_core_ops =3D core_ops;
+ core_ops.to_shortname =3D "freebsd-uthreads (corefile)";
+ core_ops.to_longname =3D "FreeBSD uthreads (corefile)";
+ core_ops.to_doc =3D "FreeBSD user threads support (for corefiles).";
+ core_ops.to_has_all_memory =3D 0;
+ core_ops.to_has_memory =3D 1;
+ core_ops.to_has_stack =3D 1;
+ core_ops.to_has_registers =3D 1;
+ core_ops.to_has_execution =3D 0;
+ core_ops.to_has_thread_control =3D tc_none;
+ core_ops.to_magic =3D OPS_MAGIC;
+ core_ops.to_pid_to_str =3D freebsd_uthread_pid_to_str;
+ core_ops.to_thread_alive =3D freebsd_utcore_thread_alive;
+ core_ops.to_attach =3D freebsd_utcore_attach;
+ core_ops.to_detach =3D freebsd_utcore_detach;
+ core_ops.to_stratum =3D core_stratum;
+ core_ops.to_find_new_threads =3D freebsd_uthread_find_new_threads;
+ core_ops.to_fetch_registers =3D freebsd_uthread_fetch_registers;
+ core_ops.to_sections =3D 0;
+ core_ops.to_sections_end =3D 0;
+}
=20
void
_initialize_freebsd_uthread ()
{
init_freebsd_uthread_ops ();
+ init_freebsd_core_ops ();
add_target (&freebsd_uthread_ops);
+ add_target (&core_ops);
=20
target_new_objfile_chain =3D target_new_objfile_hook;
target_new_objfile_hook =3D freebsd_uthread_new_objfile;
>Release-Note:
>Audit-Trail:
>Unformatted:
>threads. Severity: serious
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