Re: [patch] Fix Linux attach to signalled/stopped processes

Daniel Jacobowitz
2008-05-01T18:50:58Z

On Tue, Apr 15, 2008 at 10:31:53PM +0200, Jan Kratochvil wrote:
> Hi,
>
> please apply the attached patch to the testcase as this workaround is no longer
> required with your GDB code patch variant.

Thanks, I've merged it. Here's what I checked in.

--
Daniel Jacobowitz
CodeSourcery

2008-05-01 Daniel Jacobowitz <dan@codesourcery.com>
Pedro Alves <pedro@codesourcery.com>

Based on work by Jan Kratochvil <jan.kratochvil@redhat.com> and Jeff
Johnston <jjohnstn@redhat.com>.

* NEWS: Mention attach to stopped process fix.
* infcmd.c (detach_command, disconnect_command): Discard the thread
list.
* infrun.c (handle_inferior_event): Do not ignore non-SIGSTOP while
attaching. Use signal_stop_state.
(signal_stop_state): Check stop_soon.
* linux-nat.c (kill_lwp): Declare earlier.
(pid_is_stopped, linux_nat_post_attach_wait): New.
(lin_lwp_attach_lwp): Use linux_nat_post_attach_wait. Update
comments.
(linux_nat_attach): Use linux_nat_post_attach_wait.
(detach_callback, linux_nat_detach): Improve handling for signalled
processes.
(linux_nat_pid_to_str): Always print out the LWP ID if it differs
from the process ID.
* Makefile.in (infcmd.o): Update.

2008-05-01 Jan Kratochvil <jan.kratochvil@redhat.com>
Daniel Jacobowitz <dan@codesourcery.com>

* gdb.threads/attach-into-signal.c, gdb.threads/attach-into-signal.exp,
gdb.threads/attach-stopped.c, gdb.threads/attach-stopped.exp,
gdb.threads/attachstop-mt.c, gdb.threads/attachstop-mt.exp: New.

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.1006
diff -u -p -r1.1006 Makefile.in
--- Makefile.in 30 Apr 2008 21:19:10 -0000 1.1006
+++ Makefile.in 1 May 2008 18:47:54 -0000
@@ -2316,7 +2316,7 @@ infcmd.o: infcmd.c $(defs_h) $(gdb_strin
$(objfiles_h) $(completer_h) $(ui_out_h) $(event_top_h) \
$(parser_defs_h) $(regcache_h) $(reggroups_h) $(block_h) \
$(solib_h) $(gdb_assert_h) $(observer_h) $(target_descriptions_h) \
- $(user_regs_h) $(exceptions_h) $(cli_decode_h)
+ $(user_regs_h) $(exceptions_h) $(cli_decode_h) $(gdbthread_h)
inf-loop.o: inf-loop.c $(defs_h) $(inferior_h) $(target_h) $(event_loop_h) \
$(event_top_h) $(inf_loop_h) $(remote_h) $(exceptions_h) \
$(language_h)
Index: NEWS
===================================================================
RCS file: /cvs/src/src/gdb/NEWS,v
retrieving revision 1.268
diff -u -p -r1.268 NEWS
--- NEWS 24 Apr 2008 10:21:44 -0000 1.268
+++ NEWS 1 May 2008 18:47:54 -0000
@@ -4,11 +4,11 @@
*** Changes since GDB 6.8

* GDB now supports multiple function calling conventions according to the
- DWARF-2 DW_AT_calling_convention function attribute.
+DWARF-2 DW_AT_calling_convention function attribute.

* The SH target utilizes the aforementioned change to distinguish between gcc
- and Renesas calling convention. It also adds the new CLI commands
- `set/show sh calling-convention'.
+and Renesas calling convention. It also adds the new CLI commands
+`set/show sh calling-convention'.

* GDB can now read compressed debug sections, as produced by GNU gold
with the --compress-debug-sections=zlib flag.
@@ -21,6 +21,10 @@ which will be allocated using malloc lat
* The qXfer:libraries:read remote procotol packet now allows passing a
list of section offsets.

+* On GNU/Linux, GDB can now attach to stopped processes. Several race
+conditions handling signals delivered during attach or thread creation
+have also been fixed.
+
* New features in the GDB remote stub, gdbserver

- The "--wrapper" command-line argument tells gdbserver to use a
Index: infcmd.c
===================================================================
RCS file: /cvs/src/src/gdb/infcmd.c,v
retrieving revision 1.178
diff -u -p -r1.178 infcmd.c
--- infcmd.c 24 Apr 2008 11:43:14 -0000 1.178
+++ infcmd.c 1 May 2008 18:47:55 -0000
@@ -50,6 +50,7 @@
#include "user-regs.h"
#include "exceptions.h"
#include "cli/cli-decode.h"
+#include "gdbthread.h"

/* Functions exported for general use, in inferior.h: */

@@ -2050,6 +2051,7 @@ detach_command (char *args, int from_tty
dont_repeat (); /* Not for the faint of heart. */
target_detach (args, from_tty);
no_shared_libraries (NULL, from_tty);
+ init_thread_list ();
if (deprecated_detach_hook)
deprecated_detach_hook ();
}
@@ -2068,6 +2070,7 @@ disconnect_command (char *args, int from
dont_repeat (); /* Not for the faint of heart */
target_disconnect (args, from_tty);
no_shared_libraries (NULL, from_tty);
+ init_thread_list ();
if (deprecated_detach_hook)
deprecated_detach_hook ();
}
Index: infrun.c
===================================================================
RCS file: /cvs/src/src/gdb/infrun.c,v
retrieving revision 1.271
diff -u -p -r1.271 infrun.c
--- infrun.c 25 Apr 2008 14:50:10 -0000 1.271
+++ infrun.c 1 May 2008 18:47:55 -0000
@@ -1946,13 +1946,15 @@ handle_inferior_event (struct execution_

/* This originates from attach_command(). We need to overwrite
the stop_signal here, because some kernels don't ignore a
- SIGSTOP in a subsequent ptrace(PTRACE_SONT,SOGSTOP) call.
- See more comments in inferior.h. */
- if (stop_soon == STOP_QUIETLY_NO_SIGSTOP)
+ SIGSTOP in a subsequent ptrace(PTRACE_CONT,SIGSTOP) call.
+ See more comments in inferior.h. On the other hand, if we
+ get a non-SIGSTOP, report it to the user - assume the backend
+ will handle the SIGSTOP if it should show up later. */
+ if (stop_soon == STOP_QUIETLY_NO_SIGSTOP
+ && stop_signal == TARGET_SIGNAL_STOP)
{
stop_stepping (ecs);
- if (stop_signal == TARGET_SIGNAL_STOP)
- stop_signal = TARGET_SIGNAL_0;
+ stop_signal = TARGET_SIGNAL_0;
return;
}

@@ -2023,7 +2025,7 @@ process_event_stop_test:
target_terminal_ours_for_output ();
print_stop_reason (SIGNAL_RECEIVED, stop_signal);
}
- if (signal_stop[stop_signal])
+ if (signal_stop_state (stop_signal))
{
stop_stepping (ecs);
return;
@@ -3276,7 +3278,9 @@ hook_stop_stub (void *cmd)
int
signal_stop_state (int signo)
{
- return signal_stop[signo];
+ /* Always stop on signals if we're just gaining control of the
+ program. */
+ return signal_stop[signo] || stop_soon != NO_STOP_QUIETLY;
}

int
Index: linux-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/linux-nat.c,v
retrieving revision 1.80
diff -u -p -r1.80 linux-nat.c
--- linux-nat.c 25 Mar 2008 12:26:21 -0000 1.80
+++ linux-nat.c 1 May 2008 18:47:55 -0000
@@ -50,6 +50,30 @@
#include "event-loop.h"
#include "event-top.h"

+/* Note on this file's use of signals:
+
+ We stop threads by sending a SIGSTOP. The use of SIGSTOP instead
+ of another signal is not entirely significant; we just need for a
+ signal to be delivered, so that we can intercept it. SIGSTOP's
+ advantage is that it can not be blocked. A disadvantage is that it
+ is not a real-time signal, so it can only be queued once; we do not
+ keep track of other sources of SIGSTOP.
+
+ Two other signals that can't be blocked are SIGCONT and SIGKILL.
+ But we can't use them, because they have special behavior when the
+ signal is generated - not when it is delivered. SIGCONT resumes
+ the entire thread group and SIGKILL kills the entire thread group.
+
+ A delivered SIGSTOP would stop the entire thread group, not just the
+ thread we tkill'd. But we never let the SIGSTOP deliver; we always
+ intercept and cancel it (by PTRACE_CONT without passing SIGSTOP).
+
+ We could use a real-time signal instead. This would solve those
+ problems; we could use PTRACE_GETSIGINFO to locate the specific
+ stop signals sent by GDB. But we would still have to have some
+ support for SIGSTOP, since PTRACE_ATTACH generates it, and there
+ are races with trying to find a signal that is not blocked. */
+
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
@@ -186,6 +210,7 @@ static void linux_nat_async (void (*call
(enum inferior_event_type event_type, void *context),
void *context);
static int linux_nat_async_mask (int mask);
+static int kill_lwp (int lwpid, int signo);

/* Captures the result of a successful waitpid call, along with the
options used in that call. */
@@ -1010,10 +1035,103 @@ exit_lwp (struct lwp_info *lp)
delete_lwp (lp->ptid);
}

-/* Attach to the LWP specified by PID. If VERBOSE is non-zero, print
- a message telling the user that a new LWP has been added to the
- process. Return 0 if successful or -1 if the new LWP could not
- be attached. */
+/* Detect `T (stopped)' in `/proc/PID/status'.
+ Other states including `T (tracing stop)' are reported as false. */
+
+static int
+pid_is_stopped (pid_t pid)
+{
+ FILE *status_file;
+ char buf[100];
+ int retval = 0;
+
+ snprintf (buf, sizeof (buf), "/proc/%d/status", (int) pid);
+ status_file = fopen (buf, "r");
+ if (status_file != NULL)
+ {
+ int have_state = 0;
+
+ while (fgets (buf, sizeof (buf), status_file))
+ {
+ if (strncmp (buf, "State:", 6) == 0)
+ {
+ have_state = 1;
+ break;
+ }
+ }
+ if (have_state && strstr (buf, "T (stopped)") != NULL)
+ retval = 1;
+ fclose (status_file);
+ }
+ return retval;
+}
+
+/* Wait for the LWP specified by LP, which we have just attached to.
+ Returns a wait status for that LWP, to cache. */
+
+static int
+linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
+ int *signalled)
+{
+ pid_t new_pid, pid = GET_LWP (ptid);
+ int status;
+
+ if (pid_is_stopped (pid))
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LNPAW: Attaching to a stopped process\n");
+
+ /* The process is definitely stopped. It is in a job control
+ stop, unless the kernel predates the TASK_STOPPED /
+ TASK_TRACED distinction, in which case it might be in a
+ ptrace stop. Make sure it is in a ptrace stop; from there we
+ can kill it, signal it, et cetera.
+
+ First make sure there is a pending SIGSTOP. Since we are
+ already attached, the process can not transition from stopped
+ to running without a PTRACE_CONT; so we know this signal will
+ go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
+ probably already in the queue (unless this kernel is old
+ enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
+ is not an RT signal, it can only be queued once. */
+ kill_lwp (pid, SIGSTOP);
+
+ /* Finally, resume the stopped process. This will deliver the SIGSTOP
+ (or a higher priority signal, just like normal PTRACE_ATTACH). */
+ ptrace (PTRACE_CONT, pid, 0, 0);
+ }
+
+ /* Make sure the initial process is stopped. The user-level threads
+ layer might want to poke around in the inferior, and that won't
+ work if things haven't stabilized yet. */
+ new_pid = my_waitpid (pid, &status, 0);
+ if (new_pid == -1 && errno == ECHILD)
+ {
+ if (first)
+ warning (_("%s is a cloned process"), target_pid_to_str (ptid));
+
+ /* Try again with __WCLONE to check cloned processes. */
+ new_pid = my_waitpid (pid, &status, __WCLONE);
+ *cloned = 1;
+ }
+
+ gdb_assert (pid == new_pid && WIFSTOPPED (status));
+
+ if (WSTOPSIG (status) != SIGSTOP)
+ {
+ *signalled = 1;
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LNPAW: Received %s after attaching\n",
+ status_to_str (status));
+ }
+
+ return status;
+}
+
+/* Attach to the LWP specified by PID. Return 0 if successful or -1
+ if the new LWP could not be attached. */

int
lin_lwp_attach_lwp (ptid_t ptid)
@@ -1036,9 +1154,7 @@ lin_lwp_attach_lwp (ptid_t ptid)
to happen. */
if (GET_LWP (ptid) != GET_PID (ptid) && lp == NULL)
{
- pid_t pid;
- int status;
- int cloned = 0;
+ int status, cloned = 0, signalled = 0;

if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0)
{
@@ -1057,24 +1173,18 @@ lin_lwp_attach_lwp (ptid_t ptid)
"LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
target_pid_to_str (ptid));

- pid = my_waitpid (GET_LWP (ptid), &status, 0);
- if (pid == -1 && errno == ECHILD)
+ status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
+ lp = add_lwp (ptid);
+ lp->stopped = 1;
+ lp->cloned = cloned;
+ lp->signalled = signalled;
+ if (WSTOPSIG (status) != SIGSTOP)
{
- /* Try again with __WCLONE to check cloned processes. */
- pid = my_waitpid (GET_LWP (ptid), &status, __WCLONE);
- cloned = 1;
+ lp->resumed = 1;
+ lp->status = status;
}

- gdb_assert (pid == GET_LWP (ptid)
- && WIFSTOPPED (status) && WSTOPSIG (status));
-
- if (lp == NULL)
- lp = add_lwp (ptid);
- lp->cloned = cloned;
-
- target_post_attach (pid);
-
- lp->stopped = 1;
+ target_post_attach (GET_LWP (lp->ptid));

if (debug_linux_nat)
{
@@ -1133,10 +1243,7 @@ static void
linux_nat_attach (char *args, int from_tty)
{
struct lwp_info *lp;
- pid_t pid;
int status;
- int cloned = 0;
- int options = 0;

/* FIXME: We should probably accept a list of process id's, and
attach all of them. */
@@ -1151,54 +1258,69 @@ linux_nat_attach (char *args, int from_t
sigdelset (&suspend_mask, SIGCHLD);
}

- /* Make sure the initial process is stopped. The user-level threads
- layer might want to poke around in the inferior, and that won't
- work if things haven't stabilized yet. */
- pid = my_waitpid (GET_PID (inferior_ptid), &status, options);
- if (pid == -1 && errno == ECHILD)
- {
- warning (_("%s is a cloned process"), target_pid_to_str (inferior_ptid));
-
- /* Try again with __WCLONE to check cloned processes. */
- options = __WCLONE;
- pid = my_waitpid (GET_PID (inferior_ptid), &status, options);
- cloned = 1;
- }
-
- gdb_assert (pid == GET_PID (inferior_ptid)
- && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP);
-
/* Add the initial process as the first LWP to the list. */
inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid));
lp = add_lwp (inferior_ptid);
- lp->cloned = cloned;
+
+ status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
+ &lp->signalled);
+ lp->stopped = 1;

/* If this process is not using thread_db, then we still don't
detect any other threads, but add at least this one. */
add_thread_silent (lp->ptid);

- lp->stopped = 1;
+ /* Save the wait status to report later. */
lp->resumed = 1;
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LNA: waitpid %ld, saving status %s\n",
+ (long) GET_PID (lp->ptid), status_to_str (status));

if (!target_can_async_p ())
- {
- /* Fake the SIGSTOP that core GDB expects. */
- lp->status = W_STOPCODE (SIGSTOP);
- if (debug_linux_nat)
- fprintf_unfiltered (gdb_stdlog,
- "LNA: waitpid %ld, faking SIGSTOP\n", (long) pid);
- }
+ lp->status = status;
else
{
/* We already waited for this LWP, so put the wait result on the
pipe. The event loop will wake up and gets us to handling
this event. */
- linux_nat_event_pipe_push (pid, status, options);
+ linux_nat_event_pipe_push (GET_PID (lp->ptid), status,
+ lp->cloned ? __WCLONE : 0);
/* Register in the event loop. */
target_async (inferior_event_handler, 0);
}
}

+/* Get pending status of LP. */
+static int
+get_pending_status (struct lwp_info *lp, int *status)
+{
+ struct target_waitstatus last;
+ ptid_t last_ptid;
+
+ get_last_target_status (&last_ptid, &last);
+
+ /* If this lwp is the ptid that GDB is processing an event from, the
+ signal will be in stop_signal. Otherwise, in all-stop + sync
+ mode, we may cache pending events in lp->status while trying to
+ stop all threads (see stop_wait_callback). In async mode, the
+ events are always cached in waitpid_queue. */
+
+ *status = 0;
+ if (GET_LWP (lp->ptid) == GET_LWP (last_ptid))
+ {
+ if (stop_signal != TARGET_SIGNAL_0
+ && signal_pass_state (stop_signal))
+ *status = W_STOPCODE (target_signal_to_host (stop_signal));
+ }
+ else if (target_can_async_p ())
+ queued_waitpid (GET_LWP (lp->ptid), status, __WALL);
+ else
+ *status = lp->status;
+
+ return 0;
+}
+
static int
detach_callback (struct lwp_info *lp, void *data)
{
@@ -1209,40 +1331,30 @@ detach_callback (struct lwp_info *lp, vo
strsignal (WSTOPSIG (lp->status)),
target_pid_to_str (lp->ptid));

- while (lp->signalled && lp->stopped)
+ /* If there is a pending SIGSTOP, get rid of it. */
+ if (lp->signalled)
{
- errno = 0;
- if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0,
- WSTOPSIG (lp->status)) < 0)
- error (_("Can't continue %s: %s"), target_pid_to_str (lp->ptid),
- safe_strerror (errno));
-
if (debug_linux_nat)
fprintf_unfiltered (gdb_stdlog,
- "DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n",
- target_pid_to_str (lp->ptid),
- status_to_str (lp->status));
+ "DC: Sending SIGCONT to %s\n",
+ target_pid_to_str (lp->ptid));

- lp->stopped = 0;
+ kill_lwp (GET_LWP (lp->ptid), SIGCONT);
lp->signalled = 0;
- lp->status = 0;
- /* FIXME drow/2003-08-26: There was a call to stop_wait_callback
- here. But since lp->signalled was cleared above,
- stop_wait_callback didn't do anything; the process was left
- running. Shouldn't we be waiting for it to stop?
- I've removed the call, since stop_wait_callback now does do
- something when called with lp->signalled == 0. */
-
- gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
}

/* We don't actually detach from the LWP that has an id equal to the
overall process id just yet. */
if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
{
+ int status = 0;
+
+ /* Pass on any pending signal for this LWP. */
+ get_pending_status (lp, &status);
+
errno = 0;
if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
- WSTOPSIG (lp->status)) < 0)
+ WSTOPSIG (status)) < 0)
error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
safe_strerror (errno));

@@ -1252,7 +1364,6 @@ detach_callback (struct lwp_info *lp, vo
target_pid_to_str (lp->ptid),
strsignal (WSTOPSIG (lp->status)));

- drain_queued_events (GET_LWP (lp->ptid));
delete_lwp (lp->ptid);
}

@@ -1263,6 +1374,9 @@ static void
linux_nat_detach (char *args, int from_tty)
{
int pid;
+ int status;
+ enum target_signal sig;
+
if (target_can_async_p ())
linux_nat_async (NULL, 0);

@@ -1271,6 +1385,21 @@ linux_nat_detach (char *args, int from_t
/* Only the initial process should be left right now. */
gdb_assert (num_lwps == 1);

+ /* Pass on any pending signal for the last LWP. */
+ if ((args == NULL || *args == '\0')
+ && get_pending_status (lwp_list, &status) != -1
+ && WIFSTOPPED (status))
+ {
+ /* Put the signal number in ARGS so that inf_ptrace_detach will
+ pass it along with PTRACE_DETACH. */
+ args = alloca (8);
+ sprintf (args, "%d", (int) WSTOPSIG (status));
+ fprintf_unfiltered (gdb_stdlog,
+ "LND: Sending signal %s to %s\n",
+ args,
+ target_pid_to_str (lwp_list->ptid));
+ }
+
trap_ptid = null_ptid;

/* Destroy LWP info; it's no longer valid. */
@@ -2848,7 +2977,9 @@ linux_nat_pid_to_str (ptid_t ptid)
{
static char buf[64];

- if (lwp_list && lwp_list->next && is_lwp (ptid))
+ if (is_lwp (ptid)
+ && ((lwp_list && lwp_list->next)
+ || GET_PID (ptid) != GET_LWP (ptid)))
{
snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid));
return buf;
@@ -4205,4 +4336,3 @@ lin_thread_get_thread_signals (sigset_t
/* ... except during a sigsuspend. */
sigdelset (&suspend_mask, cancel);
}
-
Index: testsuite/gdb.threads/attach-into-signal.c
===================================================================
RCS file: testsuite/gdb.threads/attach-into-signal.c
diff -N testsuite/gdb.threads/attach-into-signal.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/attach-into-signal.c 1 May 2008 18:47:55 -0000
@@ -0,0 +1,67 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2008 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <signal.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef USE_THREADS
+#include <pthread.h>
+#endif
+
+void action(int sig, siginfo_t * info, void *uc)
+{
+ raise (SIGALRM);
+}
+
+static void *func (void *arg)
+{
+ struct sigaction act;
+
+ memset (&act, 0, sizeof(struct sigaction));
+ act.sa_sigaction = action;
+ act.sa_flags = SA_RESTART;
+ sigaction (SIGALRM, &act, 0);
+
+ raise (SIGALRM);
+
+ /* We must not get past this point, either in a free standing or debugged
+ state. */
+
+ abort ();
+ /* NOTREACHED */
+ return NULL;
+}
+
+int main ()
+{
+
+#ifndef USE_THREADS
+
+ func (NULL);
+
+#else
+
+ pthread_t th;
+ pthread_create (&th, NULL, func, NULL);
+ pthread_join (th, NULL);
+
+#endif
+
+ return 0;
+}
Index: testsuite/gdb.threads/attach-into-signal.exp
===================================================================
RCS file: testsuite/gdb.threads/attach-into-signal.exp
diff -N testsuite/gdb.threads/attach-into-signal.exp
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/attach-into-signal.exp 1 May 2008 18:47:55 -0000
@@ -0,0 +1,168 @@
+# Copyright 2008
+# Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This test was created by modifying attach-stopped.exp.
+# This file was created by Jan Kratochvil <jan.kratochvil@redhat.com>.
+
+# This test only works on Linux
+if { ![isnative] || [is_remote host] || ![istarget *-linux*] } {
+ continue
+}
+
+set testfile "attach-into-signal"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+set escapedbinfile [string_to_regexp ${objdir}/${subdir}/${testfile}]
+
+remote_exec build "rm -f ${binfile}"
+# For debugging this test
+#
+#log_user 1
+
+proc corefunc { threadtype } {
+ global srcfile
+ global binfile
+ global escapedbinfile
+ global srcdir
+ global subdir
+ global gdb_prompt
+
+ if [get_compiler_info ${binfile}] {
+ return -1
+ }
+
+ # Start the program running and then wait for a bit, to be sure
+ # that it can be attached to.
+ # Statistically there is a better chance without giving process a nice.
+
+ set testpid [eval exec $binfile &]
+ exec sleep 2
+
+ # Run 2 passes of the test.
+ # The C file inferior stops pending its signals if a single one is lost,
+ # we test successful redelivery of the caught signal by the 2nd pass.
+
+ # linux-2.6.20.4.x86_64 had maximal attempt # 20 in 4 test runs.
+ set attempts 100
+ set attempt 1
+ set passes 1
+ while { $passes < 3 && $attempt <= $attempts } {
+ set stoppedtry 0
+ while { $stoppedtry < 10 } {
+ if [catch {open /proc/${testpid}/status r} fileid] {
+ set stoppedtry 10
+ break
+ }
+ gets $fileid line1;
+ gets $fileid line2;
+ close $fileid;
+
+ if {![string match "*(stopped)*" $line2]} {
+ # No PASS message as we may be looping in multiple attempts.
+ break
+ }
+ sleep 1
+ set stoppedtry [expr $stoppedtry + 1]
+ }
+ if { $stoppedtry >= 10 } {
+ verbose -log $line2
+ set test "$threadtype: process is still running on the attempt # $attempt of $attempts"
+ break
+ }
+
+ # Main test:
+ set test "$threadtype: attach (pass $passes), pending signal catch"
+ if {[gdb_test_multiple "attach $testpid" $test {
+ -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*Received Alarm clock.*$gdb_prompt $" {
+ # nonthreaded:
+ pass $test
+ verbose -log "$test succeeded on the attempt # $attempt of $attempts"
+ set passes [expr $passes + 1]
+ }
+ -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+ # nonthreaded:
+ # We just lack the luck, we should try it again.
+ set attempt [expr $attempt + 1]
+ }
+ -re "Attaching to process $testpid.*Received Alarm clock.*$gdb_prompt $" {
+ # threaded:
+ pass $test
+ verbose -log "$test succeeded on the attempt # $attempt of $attempts"
+ set passes [expr $passes + 1]
+ }
+ -re "Attaching to process $testpid.*$gdb_prompt $" {
+ # threaded:
+ # We just lack the luck, we should try it again.
+ set attempt [expr $attempt - 1]
+ }
+ }] != 0 } {
+ break
+ }
+
+ gdb_test "detach" "Detaching from.*" ""
+ }
+ if {$passes < 3} {
+ if {$attempt > $attempts} {
+ unresolved $test
+ } else {
+ fail $test
+ }
+ }
+
+ # Exit and detach the process.
+
+ gdb_exit
+
+ # Make sure we don't leave a process around to confuse
+ # the next test run (and prevent the compile by keeping
+ # the text file busy), in case the "set should_exit" didn't
+ # work.
+
+ # Continue the program - some Linux kernels need it before -9 if the
+ # process is stopped.
+ remote_exec build "kill -s CONT ${testpid}"
+
+ remote_exec build "kill -9 ${testpid}"
+}
+
+# Start with clean gdb
+gdb_exit
+
+# build the test case first without threads
+#
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ gdb_suppress_entire_file "Testcase nonthraded compile failed, so all tests in this file will automatically fail."
+}
+
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+gdb_test "set debug lin-lwp 1" "" ""
+
+corefunc nonthreaded
+
+# build the test case also with threads
+#
+if { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug additional_flags=-DUSE_THREADS}] != "" } {
+ gdb_suppress_entire_file "Testcase threaded compile failed, so all tests in this file will automatically fail."
+}
+
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+gdb_test "set debug lin-lwp 1" "" ""
+
+corefunc threaded
Index: testsuite/gdb.threads/attach-stopped.c
===================================================================
RCS file: testsuite/gdb.threads/attach-stopped.c
diff -N testsuite/gdb.threads/attach-stopped.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/attach-stopped.c 1 May 2008 18:47:55 -0000
@@ -0,0 +1,50 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2008 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* This program is intended to be started outside of gdb, then
+ manually stopped via a signal. */
+
+#include <stddef.h>
+#include <unistd.h>
+#ifdef USE_THREADS
+#include <pthread.h>
+#endif
+
+static void *func (void *arg)
+{
+ sleep (10000); /* Ridiculous time, but we will eventually kill it. */
+ sleep (10000); /* Second sleep. */
+ return NULL;
+}
+
+int main ()
+{
+
+#ifndef USE_THREADS
+
+ func (NULL);
+
+#else
+
+ pthread_t th;
+ pthread_create (&th, NULL, func, NULL);
+ pthread_join (th, NULL);
+
+#endif
+
+ return 0;
+}
Index: testsuite/gdb.threads/attach-stopped.exp
===================================================================
RCS file: testsuite/gdb.threads/attach-stopped.exp
diff -N testsuite/gdb.threads/attach-stopped.exp
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/attach-stopped.exp 1 May 2008 18:47:55 -0000
@@ -0,0 +1,157 @@
+# Copyright 2008
+# Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This test was created by modifying attach.exp.
+# This file was created by Jeff Johnston <jjohnstn@redhat.com>.
+# This file was updated by Jan Kratochvil <jan.kratochvil@redhat.com>.
+
+# This test only works on Linux
+if { ![isnative] || [is_remote host] || ![istarget *-linux*] } {
+ continue
+}
+
+set testfile "attach-stopped"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+set escapedbinfile [string_to_regexp ${objdir}/${subdir}/${testfile}]
+
+#execute_anywhere "rm -f ${binfile}"
+remote_exec build "rm -f ${binfile}"
+# For debugging this test
+#
+#log_user 1
+
+proc corefunc { threadtype } {
+ global srcfile
+ global binfile
+ global escapedbinfile
+ global srcdir
+ global subdir
+ global gdb_prompt
+
+ if [get_compiler_info ${binfile}] {
+ return -1
+ }
+
+ # Start the program running and then wait for a bit, to be sure
+ # that it can be attached to.
+
+ set testpid [eval exec $binfile &]
+
+ # Avoid some race:
+ sleep 2
+
+ # Stop the program
+ remote_exec build "kill -s STOP ${testpid}"
+
+ # Start with clean gdb
+ gdb_exit
+ gdb_start
+ gdb_reinitialize_dir $srcdir/$subdir
+ gdb_load ${binfile}
+
+ # Verify that we can attach to the stopped process.
+
+ set test "$threadtype: attach2 to stopped, after setting file"
+ gdb_test_multiple "attach $testpid" "$test" {
+ -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+ pass "$test"
+ }
+ }
+
+ # ".*sleep.*clone.*" would fail on s390x as bt stops at START_THREAD there.
+ if {[string equal $threadtype threaded]} {
+ gdb_test "thread apply all bt" ".*sleep.*start_thread.*" "$threadtype: attach2 to stopped bt"
+ } else {
+ gdb_test "bt" ".*sleep.*main.*" "$threadtype: attach2 to stopped bt"
+ }
+ # This breakpoint is there for old/non-x86 kernels not restarting syscalls.
+ gdb_breakpoint [gdb_get_line_number "Second sleep"]
+ set test "$threadtype: attach2 continue"
+ send_gdb "continue\n"
+ gdb_expect {
+ -re "Continuing"
+ { pass "continue ($test)" }
+ timeout
+ { fail "continue ($test) (timeout)" }
+ }
+
+ # For this to work we must be sure to consume the "Continuing."
+ # message first, or GDB's signal handler may not be in place.
+ after 1000 {send_gdb "\003"}
+ set test "$threadtype: attach2 stop interrupt"
+ gdb_expect 10 {
+ -re "Program received signal SIGINT.*$gdb_prompt $"
+ {
+ pass $test
+ }
+ -re "Breakpoint \[0-9\].*$srcfile.*$gdb_prompt $"
+ {
+ pass $test
+ }
+ timeout
+ {
+ fail $test
+ }
+ }
+
+ gdb_exit
+
+ # Avoid some race:
+ sleep 2
+
+ # At this point, the process should be sleeping
+
+ if [catch {open /proc/${testpid}/status r} fileid2] {
+ set line2 "NOTFOUND"
+ } else {
+ gets $fileid2 line1;
+ gets $fileid2 line2;
+ close $fileid2;
+ }
+
+ set test "$threadtype: attach2, exit leaves process sleeping"
+ if {[string match "*(sleeping)*" $line2]} {
+ pass $test
+ } else {
+ fail $test
+ }
+
+ # Make sure we don't leave a process around to confuse
+ # the next test run (and prevent the compile by keeping
+ # the text file busy), in case the "set should_exit" didn't
+ # work.
+
+ remote_exec build "kill -9 ${testpid}"
+}
+
+# build the test case first without threads
+#
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ gdb_suppress_entire_file "Testcase nonthraded compile failed, so all tests in this file will automatically fail."
+}
+
+corefunc nonthreaded
+
+# build the test case first without threads
+#
+if { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug additional_flags=-DUSE_THREADS}] != "" } {
+ gdb_suppress_entire_file "Testcase threaded compile failed, so all tests in this file will automatically fail."
+}
+
+corefunc threaded
+
+return 0
Index: testsuite/gdb.threads/attachstop-mt.c
===================================================================
RCS file: testsuite/gdb.threads/attachstop-mt.c
diff -N testsuite/gdb.threads/attachstop-mt.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/attachstop-mt.c 1 May 2008 18:47:55 -0000
@@ -0,0 +1,55 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2008 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* This program is intended to be started outside of gdb, then
+ manually stopped via a signal. */
+
+#include <unistd.h>
+#include <pthread.h>
+#include <stdio.h>
+
+/* Red Hat BZ PR 197584.c */
+
+void *func (void *arg)
+{
+ sleep (10000); /* Ridiculous time, but we will eventually kill it. */
+ sleep (10000); /* RHEL3U8 kernel-2.4.21-47.EL will cut the sleep time. */
+
+ return NULL; /* thread-sleep */
+}
+
+int main ()
+{
+ pthread_t t1,t2;
+ int ret;
+
+ ret = pthread_create (&t1, NULL, func, NULL);
+ if (ret)
+ fprintf(stderr, "pthread_create(): %s", strerror (ret));
+ ret = pthread_create (&t2, NULL, func, NULL);
+ if (ret)
+ fprintf(stderr, "pthread_create(): %s", strerror (ret));
+
+ ret = pthread_join (t1, NULL);
+ if (ret) /* first-join */
+ fprintf(stderr, "pthread_join(): %s", strerror (ret));
+ ret = pthread_join (t2, NULL);
+ if (ret)
+ fprintf(stderr, "pthread_join(): %s", strerror (ret));
+
+ return 0;
+}
Index: testsuite/gdb.threads/attachstop-mt.exp
===================================================================
RCS file: testsuite/gdb.threads/attachstop-mt.exp
diff -N testsuite/gdb.threads/attachstop-mt.exp
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/attachstop-mt.exp 1 May 2008 18:47:55 -0000
@@ -0,0 +1,260 @@
+# Copyright 2008
+# Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This test was created by modifying gdb.threads/attachstop.
+# This file was created by Jan Kratochvil <jan.kratochvil@redhat.com>.
+# Regression for: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=197584
+
+# This test only works on Linux
+if { ![isnative] || [is_remote host] || ![istarget *-linux*] } {
+ continue
+}
+
+set testfile "attachstop-mt"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+set escapedbinfile [string_to_regexp ${objdir}/${subdir}/${testfile}]
+
+#execute_anywhere "rm -f ${binfile}"
+remote_exec build "rm -f ${binfile}"
+# For debugging this test
+#
+#log_user 1
+
+# build the test case
+#
+if { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
+}
+
+if [get_compiler_info ${binfile}] {
+ return -1
+}
+
+# Start the program running and then wait for a bit, to be sure
+# that it can be attached to.
+
+set testpid [eval exec $binfile &]
+
+# No race
+sleep 2
+
+# Do not: set testpid2 [expr $testpid + 1]
+# as it will not exist on Red Hat 2.6.9-34.0.2.ELsmp
+set testpid2 [expr $testpid + 2]
+
+set status2 /proc/${testpid}/task/${testpid2}/status
+if {[expr ! [file exists $status2]]} {
+ # kernel-2.4
+ set status2 /proc/${testpid2}/status
+}
+
+# Initial sanity test it is normally sleeping
+set fileid0 [open $status2 r];
+gets $fileid0 line1;
+gets $fileid0 line2;
+close $fileid0;
+
+set test "attach0, initial sanity check of the sleeping state"
+if {[string match "*(sleeping)*" $line2]} {
+ pass $test
+} else {
+ fail $test
+}
+
+# Sttach and detach to test it will not become stopped
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+set test "attach0 to sleeping"
+gdb_test_multiple "attach $testpid" "$test" {
+ -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+ pass "$test"
+ }
+}
+
+gdb_test "gcore /dev/null" ".*aved corefile.*" "attach0 to sleeping gcore invocation"
+
+gdb_test "thread 2" ".*witching to thread 2 .*" "attach0 to sleeping switch thread"
+
+gdb_test "bt" ".*sleep.*func.*" "attach0 to sleeping bt"
+
+# Exit and detach the process.
+
+gdb_exit
+
+# No race
+sleep 2
+
+# Check it did not get stopped by our gdb
+set fileid1 [open $status2 r];
+gets $fileid1 line1;
+gets $fileid1 line2;
+close $fileid1;
+
+set test "attach1, post-gdb sanity check of the sleeping state - Red Hat BZ 197584"
+if {[string match "*(sleeping)*" $line2]} {
+ pass $test
+} else {
+ fail $test
+}
+
+# Stop the program
+remote_exec build "kill -s STOP ${testpid}"
+
+# No race
+sleep 2
+
+# Check it really got stopped by kill(1)
+set fileid2 [open $status2 r];
+gets $fileid2 line1;
+gets $fileid2 line2;
+close $fileid2;
+
+set test "attach2, initial sanity check of the stopped state"
+if {[string match "*(stopped)*" $line2]} {
+ pass $test
+} else {
+ fail $test
+}
+
+# Start with clean gdb
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# Verify that we can attach to the process by first giving its
+# executable name via the file command, and using attach with the
+# process ID.
+
+set test "set file, before attach3 to stopped process"
+gdb_test_multiple "file $binfile" "$test" {
+ -re "Load new symbol table from.*y or n. $" {
+ gdb_test "y" "Reading symbols from $escapedbinfile\.\.\.*done." \
+ "$test (re-read)"
+ }
+ -re "Reading symbols from $escapedbinfile\.\.\.*done.*$gdb_prompt $" {
+ pass "$test"
+ }
+}
+
+set test "attach3 to stopped, after setting file"
+gdb_test_multiple "attach $testpid" "$test" {
+ -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+ pass "$test"
+ }
+}
+
+# We may be already after the threads phase.
+# `thread 2' command is important for the test to switch the current thread to
+# a non-primary one for the detach process.
+
+gdb_test "thread 2" ".*(witching to thread 2 |hread ID 2 not known).*" "attach3 to stopped switch thread"
+gdb_test "bt" ".*sleep.*(func|main).*" "attach3 to stopped bt"
+
+# Exit and detach the process.
+gdb_exit
+
+# Stop the program
+remote_exec build "kill -s STOP ${testpid}"
+
+# No race
+sleep 2
+
+# Continue the test as we would hit another expected bug regarding
+# Program received signal SIGSTOP, Stopped (signal).
+# across NPTL threads.
+
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# Verify that we can attach to the process just by giving the
+# process ID.
+
+set test "attach4 to stopped, after setting file"
+gdb_test_multiple "attach $testpid" "$test" {
+ -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+ pass "$test"
+ }
+}
+
+# We may be already after the threads phase.
+# `thread 2' command is important for the test to switch the current thread to
+# a non-primary one for the detach process.
+
+gdb_test "thread 2" ".*(witching to thread 2 |hread ID 2 not known).*" "attach4 to stopped switch thread"
+gdb_test "bt" ".*sleep.*(func|main).*" "attach4 to stopped bt"
+
+# RHEL3U8 kernel-2.4.21-47.EL will not return SIGINT but only shorten the sleep.
+gdb_breakpoint [gdb_get_line_number "Ridiculous time"]
+gdb_breakpoint [gdb_get_line_number "cut the sleep time"]
+set test "attach4 continue"
+send_gdb "continue\n"
+gdb_expect {
+ -re "Continuing"
+ { pass "continue ($test)" }
+ timeout
+ { fail "continue ($test) (timeout)" }
+}
+
+# For this to work we must be sure to consume the "Continuing."
+# message first, or GDB's signal handler may not be in place.
+after 1000 {send_gdb "\003"}
+set test "attach4 stop by interrupt"
+gdb_expect {
+ -re "Program received signal SIGINT.*$gdb_prompt $"
+ {
+ pass $test
+ }
+ -re "Breakpoint \[0-9\].*$srcfile.*$gdb_prompt $"
+ {
+ pass $test
+ }
+ timeout
+ {
+ fail "$test (timeout)"
+ }
+}
+
+gdb_exit
+
+# No race
+sleep 2
+
+# At this point, the process should be sleeping
+
+set fileid4 [open $status2 r];
+gets $fileid4 line1;
+gets $fileid4 line2;
+close $fileid4;
+
+set test "attach4, exit leaves process sleeping"
+if {[string match "*(sleeping)*" $line2]} {
+ pass $test
+} else {
+ fail $test
+}
+
+# Make sure we don't leave a process around to confuse
+# the next test run (and prevent the compile by keeping
+# the text file busy), in case the "set should_exit" didn't
+# work.
+
+remote_exec build "kill -9 ${testpid}"
+
+return 0