gdb/

	Fix watchpoints across inferior fork.
	* amd64-linux-nat.c (update_debug_registers_callback): Update the
	comment for linux_nat_iterate_watchpoint_lwps.
	(amd64_linux_dr_set_control, amd64_linux_dr_set_addr): Use
	linux_nat_iterate_watchpoint_lwps.
	(amd64_linux_prepare_to_resume): New comment on Linux kernel.
	* i386-linux-nat.c (update_debug_registers_callback): Update the
	comment for linux_nat_iterate_watchpoint_lwps.
	(i386_linux_dr_set_control, i386_linux_dr_set_addr): Use
	linux_nat_iterate_watchpoint_lwps.
	(i386_linux_prepare_to_resume): New comment on Linux kernel.
	* i386-nat.c: Include inferior.h.
	(dr_mirror): Remove.
	(i386_inferior_data, struct i386_inferior_data)
	(i386_inferior_data_get): New.
	(i386_debug_reg_state): Use i386_inferior_data_get.
	(i386_cleanup_dregs, i386_update_inferior_debug_regs)
	(i386_insert_watchpoint, i386_remove_watchpoint)
	(i386_stopped_data_address, i386_insert_hw_breakpoint)
	(i386_remove_hw_breakpoint): New variable state, use
	i386_debug_reg_state instead of DR_MIRROR.
	* linux-nat.c (delete_lwp): New declaration.
	(num_lwps): Move here from downwards.
	(delete_lwp_cleanup): New.
	(linux_child_follow_fork): Create new child_lp, call
	linux_nat_new_thread and linux_nat_prepare_to_resume before calling
	PTRACE_DETACH.
	(num_lwps): Move upwards.
	(linux_nat_iterate_watchpoint_lwps): New.
	* linux-nat.h (linux_nat_iterate_watchpoint_lwps_ftype): New.
	(linux_nat_iterate_watchpoint_lwps_ftype): New declaration.

gdb/testsuite/
	Fix watchpoints across inferior fork.
	* gdb.threads/watchpoint-fork-child.c: New file.
	* gdb.threads/watchpoint-fork-mt.c: New file.
	* gdb.threads/watchpoint-fork-parent.c: New file.
	* gdb.threads/watchpoint-fork-st.c: New file.
	* gdb.threads/watchpoint-fork.exp: New file.
	* gdb.threads/watchpoint-fork.h: New file.

6 files changed, 633 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.threads/watchpoint-fork-child.c b/gdb/testsuite/gdb.threads/watchpoint-fork-child.c
new file mode 100644
index 0000000..7a7e07f
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/watchpoint-fork-child.c
@@ -0,0 +1,129 @@
+/* Test case for forgotten hw-watchpoints after fork()-off of a process.
+
+   Copyright 2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <assert.h>
+#include <signal.h>
+#include <stdio.h>
+
+#include "watchpoint-fork.h"
+
+/* `pid_t' may not be available.  */
+
+static volatile int usr1_got;
+
+static void
+handler_usr1 (int signo)
+{
+  usr1_got++;
+}
+
+void
+forkoff (int nr)
+{
+  int child, save_parent = getpid ();
+  int i;
+  struct sigaction act, oldact;
+#ifdef THREAD
+  void *thread_result;
+#endif
+
+  memset (&act, 0, sizeof act);
+  act.sa_flags = SA_RESTART;
+  act.sa_handler = handler_usr1;
+  sigemptyset (&act.sa_mask);
+  i = sigaction (SIGUSR1, &act, &oldact);
+  assert (i == 0);
+
+  child = fork ();
+  switch (child)
+    {
+    case -1:
+      assert (0);
+    default:
+      printf ("parent%d: %d\n", nr, (int) child);
+
+      /* Sleep for a while to possibly get incorrectly ATTACH_THREADed by GDB
+	 tracing the child fork with no longer valid thread/lwp entries of the
+	 parent.  */
+
+      i = sleep (2);
+      assert (i == 0);
+
+      /* We must not get caught here (against a forgotten breakpoint).  */
+
+      var++;
+      marker ();
+
+#ifdef THREAD
+      /* And neither got caught our thread.  */
+
+      step = 99;
+      i = pthread_join (thread, &thread_result);
+      assert (i == 0);
+      assert (thread_result == (void *) 99UL);
+#endif
+
+      /* Be sure our child knows we did not get caught above.  */
+
+      i = kill (child, SIGUSR1);
+      assert (i == 0);
+
+      /* Sleep for a while to check GDB's `info threads' no longer tracks us in
+	 the child fork.  */
+
+      i = sleep (2);
+      assert (i == 0);
+
+      _exit (0);
+    case 0:
+      printf ("child%d: %d\n", nr, (int) getpid ());
+
+      /* Let the parent signal us about its success.  Be careful of races.  */
+
+      for (;;)
+	{
+	  /* Parent either died (and USR1_GOT is zero) or it succeeded.  */
+	  if (getppid () != save_parent)
+	    break;
+	  if (kill (getppid (), 0) != 0)
+	    break;
+	  /* Parent succeeded?  */
+	  if (usr1_got)
+	    break;
+
+#ifdef THREAD
+	  i = pthread_yield ();
+	  assert (i == 0);
+#endif
+	}
+      assert (usr1_got);
+
+      /* We must get caught here (against a false watchpoint removal).  */
+
+      marker ();
+    }
+
+  i = sigaction (SIGUSR1, &oldact, NULL);
+  assert (i == 0);
+}
diff --git a/gdb/testsuite/gdb.threads/watchpoint-fork-mt.c b/gdb/testsuite/gdb.threads/watchpoint-fork-mt.c
new file mode 100644
index 0000000..eb07409
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/watchpoint-fork-mt.c
@@ -0,0 +1,174 @@
+/* Test case for forgotten hw-watchpoints after fork()-off of a process.
+
+   Copyright 2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <assert.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+#include <asm/unistd.h>
+#include <unistd.h>
+#define gettid() syscall (__NR_gettid)
+
+#include "watchpoint-fork.h"
+
+/* Non-atomic `var++' should not hurt as we synchronize the threads by the STEP
+   variable.  Hit-comments need to be duplicated there to catch both at-stops
+   and behind-stops, depending on the target.  */
+
+volatile int var;
+
+void
+marker (void)
+{
+}
+
+static void
+empty (void)
+{
+}
+
+static void
+mark_exit (void)
+{
+}
+
+pthread_t thread;
+volatile int step;
+
+static void *
+start (void *arg)
+{
+  int i;
+
+  if (step >= 3)
+    goto step_3;
+
+  while (step != 1)
+    {
+      i = pthread_yield ();
+      assert (i == 0);
+    }
+
+  var++;	/* validity-thread-B */
+  empty ();	/* validity-thread-B */
+  step = 2;
+  while (step != 3)
+    {
+      if (step == 99)
+	goto step_99;
+
+      i = pthread_yield ();
+      assert (i == 0);
+    }
+
+step_3:
+  if (step >= 5)
+    goto step_5;
+
+  var++;	/* after-fork1-B */
+  empty ();	/* after-fork1-B */
+  step = 4;
+  while (step != 5)
+    {
+      if (step == 99)
+	goto step_99;
+
+      i = pthread_yield ();
+      assert (i == 0);
+    }
+
+step_5:
+  var++;	/* after-fork2-B */
+  empty ();	/* after-fork2-B */
+  return (void *) 5UL;
+
+step_99:
+  /* We must not get caught here (against a forgotten breakpoint).  */
+  var++;
+  marker ();
+  return (void *) 99UL;
+}
+
+int
+main (void)
+{
+  int i;
+  void *thread_result;
+
+  setbuf (stdout, NULL);
+  printf ("main: %d\n", (int) gettid ());
+
+  /* General hardware breakpoints and watchpoints validity.  */
+  marker ();
+  var++;	/* validity-first */
+  empty ();	/* validity-first */
+
+  i = pthread_create (&thread, NULL, start, NULL);
+  assert (i == 0);
+
+  var++;	/* validity-thread-A */
+  empty ();	/* validity-thread-A */
+  step = 1;
+  while (step != 2)
+    {
+      i = pthread_yield ();
+      assert (i == 0);
+    }
+
+  /* Hardware watchpoints got disarmed here.  */
+  forkoff (1);
+
+  var++;	/* after-fork1-A */
+  empty ();	/* after-fork1-A */
+  step = 3;
+#ifdef FOLLOW_CHILD
+  /* Spawn new thread as it was deleted in the child of FORK.  */
+  i = pthread_create (&thread, NULL, start, NULL);
+  assert (i == 0);
+#endif
+  while (step != 4)
+    {
+      i = pthread_yield ();
+      assert (i == 0);
+    }
+
+  /* A sanity check for double hardware watchpoints removal.  */
+  forkoff (2);
+
+  var++;	/* after-fork2-A */
+  empty ();	/* after-fork2-A */
+  step = 5;
+#ifdef FOLLOW_CHILD
+  /* Spawn new thread as it was deleted in the child of FORK.  */
+  i = pthread_create (&thread, NULL, start, NULL);
+  assert (i == 0);
+#endif
+
+  i = pthread_join (thread, &thread_result);
+  assert (i == 0);
+  assert (thread_result == (void *) 5UL);
+
+  mark_exit ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.threads/watchpoint-fork-parent.c b/gdb/testsuite/gdb.threads/watchpoint-fork-parent.c
new file mode 100644
index 0000000..9bbf438
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/watchpoint-fork-parent.c
@@ -0,0 +1,74 @@
+/* Test case for forgotten hw-watchpoints after fork()-off of a process.
+
+   Copyright 2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <assert.h>
+#include <stdio.h>
+#include <sys/wait.h>
+
+#include "watchpoint-fork.h"
+
+void
+forkoff (int nr)
+{
+  pid_t child, pid_got;
+  int exit_code = 42 + nr;
+  int status, i;
+
+  child = fork ();
+  switch (child)
+    {
+    case -1:
+      assert (0);
+    case 0:
+      printf ("child%d: %d\n", nr, (int) getpid ());
+      /* Delay to get both the "child%d" and "parent%d" message printed without
+	 a race breaking expect by its endless wait on `$gdb_prompt$':
+	 Breakpoint 3, marker () at ../../../gdb/testsuite/gdb.threads/watchpoint-fork.c:33
+	 33      }
+	 (gdb) parent2: 14223  */
+      i = sleep (1);
+      assert (i == 0);
+
+      /* We must not get caught here (against a forgotten breakpoint).  */
+      var++;
+      marker ();
+
+      _exit (exit_code);
+    default:
+      printf ("parent%d: %d\n", nr, (int) child);
+      /* Delay to get both the "child%d" and "parent%d" message printed, see
+	 above.  */
+      i = sleep (1);
+      assert (i == 0);
+
+      pid_got = wait (&status);
+      assert (pid_got == child);
+      assert (WIFEXITED (status));
+      assert (WEXITSTATUS (status) == exit_code);
+
+      /* We must get caught here (against a false watchpoint removal).  */
+      marker ();
+    }
+}
diff --git a/gdb/testsuite/gdb.threads/watchpoint-fork-st.c b/gdb/testsuite/gdb.threads/watchpoint-fork-st.c
new file mode 100644
index 0000000..17cc058
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/watchpoint-fork-st.c
@@ -0,0 +1,61 @@
+/* Test case for forgotten hw-watchpoints after fork()-off of a process.
+
+   Copyright 2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <assert.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "watchpoint-fork.h"
+
+volatile int var;
+
+void
+marker (void)
+{
+}
+
+static void
+mark_exit (void)
+{
+}
+
+int
+main (void)
+{
+  setbuf (stdout, NULL);
+  printf ("main: %d\n", (int) getpid ());
+
+  /* General hardware breakpoints and watchpoints validity.  */
+  marker ();
+  var++;
+  /* Hardware watchpoints got disarmed here.  */
+  forkoff (1);
+  /* This watchpoint got lost before.  */
+  var++;
+  /* A sanity check for double hardware watchpoints removal.  */
+  forkoff (2);
+  var++;
+
+  mark_exit ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.threads/watchpoint-fork.exp b/gdb/testsuite/gdb.threads/watchpoint-fork.exp
new file mode 100644
index 0000000..814fb02
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/watchpoint-fork.exp
@@ -0,0 +1,163 @@
+# Copyright 2012 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/>.
+
+# Test case for forgotten hw-watchpoints after fork()-off of a process.
+
+set testfile watchpoint-fork
+
+if [is_remote target] {
+    kfail "remote/13584" "gdbserver does not support debugging across fork"
+    return
+}
+
+proc test {type symbol} {
+    global testfile objdir subdir srcdir gdb_prompt
+
+    global pf_prefix
+    set prefix_test $pf_prefix
+    lappend pf_prefix "$type:"
+    set prefix_mt $pf_prefix
+
+    set srcfile_type ${srcdir}/${subdir}/${testfile}-${type}.c
+
+
+    # no threads
+
+    set pf_prefix $prefix_mt
+    lappend pf_prefix "singlethreaded:"
+
+    set executable ${testfile}-${type}-st
+    set srcfile_main ${srcdir}/${subdir}/${testfile}-st.c
+    if { [gdb_compile "${srcfile_main} ${srcfile_type}" ${objdir}/${subdir}/${executable} executable [list debug additional_flags=-D$symbol]] != "" } {
+	untested ${testfile}.exp
+	set pf_prefix $prefix_test
+	return
+    }
+    clean_restart $executable
+
+    if [target_info exists gdb,no_hardware_watchpoints] {
+	# The software watchpoint functionality is in GDB an unrelated test.
+	gdb_test_no_output "set can-use-hw-watchpoints 0"
+    }
+
+    gdb_test "show detach-on-fork" "Whether gdb will detach the child of a fork is on\\."
+    gdb_test_no_output "set follow-fork-mode $type"
+    gdb_test "show follow-fork-mode" "Debugger response to a program call of fork or vfork is \"$type\"\\."
+    # Testcase uses it for the `follow-fork-mode child' type.
+    gdb_test "handle SIGUSR1 nostop noprint pass" "No\[ \t\]+No\[ \t\]+Yes.*"
+
+    if ![runto_main] {
+	set pf_prefix $prefix_test
+	return
+    }
+
+    gdb_test "watch var" "atchpoint \[0-9\]+: var" "Set the watchpoint"
+
+    # It is never hit but it should not be left over in the fork()ed-off child.
+    if [skip_hw_breakpoint_tests] {
+	set hbreak "break"
+    } else {
+	set hbreak "hbreak"
+    }
+    gdb_test "$hbreak marker"
+
+    gdb_breakpoint "mark_exit"
+
+    gdb_test "continue" \
+	     "reakpoint \[0-9\]+, marker.*" "hardware breakpoints work"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 0.*New value = 1.*forkoff *\\(1\\).*" "watchpoints work"
+    gdb_test "continue" \
+	     "reakpoint \[0-9\]+, marker.*" "breakpoint after the first fork"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 1.*New value = 2.*forkoff *\\(2\\).*" "watchpoint after the first fork"
+    gdb_test "continue" \
+	     "reakpoint \[0-9\]+, marker.*" "breakpoint after the second fork"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 2.*New value = 3.*mark_exit \\(\\);" "watchpoint after the second fork"
+    gdb_test "continue" "Continuing\\..*\r\nBreakpoint \[0-9\]+, mark_exit .*" "finish"
+
+
+    # threads
+
+    if [target_info exists gdb,no_hardware_watchpoints] {
+	# Watchpoint hits would get detected in unexpected threads.
+	set pf_prefix $prefix_test
+	return
+    }
+
+    set pf_prefix $prefix_mt
+    lappend pf_prefix "multithreaded:"
+
+    set executable ${testfile}-${type}-mt
+    set srcfile_main ${srcdir}/${subdir}/${testfile}-mt.c
+    if { [gdb_compile_pthreads "${srcfile_main} ${srcfile_type}" ${objdir}/${subdir}/${executable} executable [list debug "additional_flags=-D$symbol -DTHREAD"]] != "" } {
+	untested ${testfile}.exp
+	set pf_prefix $prefix_test
+	return
+    }
+    clean_restart $executable
+
+    gdb_test_no_output "set follow-fork-mode $type"
+    # Testcase uses it for the `follow-fork-mode child' type.
+    gdb_test "handle SIGUSR1 nostop noprint pass" "No\[ \t\]+No\[ \t\]+Yes.*"
+
+    if ![runto_main] {
+	set pf_prefix $prefix_test
+	return
+    }
+
+    gdb_test "watch var" "atchpoint \[0-9\]+: var" "Set the watchpoint"
+
+    # It should not be left over in the fork()ed-off child.
+    gdb_test "$hbreak marker" {reakpoint [0-9]+.*}
+
+    gdb_breakpoint "mark_exit"
+
+    gdb_test "continue" \
+	     "reakpoint \[0-9\]+, marker.*" "hardware breakpoints work"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 0.*New value = 1.*validity-first.*" "singlethread watchpoints work"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 1.*New value = 2.*validity-thread-A.*" "multithreaded watchpoints work at A"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 2.*New value = 3.*validity-thread-B.*" "multithreaded watchpoints work at B"
+    gdb_test "continue" \
+	     "reakpoint \[0-9\]+, marker.*" "breakpoint (A) after the first fork"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 3.*New value = 4.*after-fork1-A.*" "watchpoint A after the first fork"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 4.*New value = 5.*after-fork1-B.*" "watchpoint B after the first fork"
+    gdb_test "continue" \
+	     "reakpoint \[0-9\]+, marker.*" "breakpoint (A) after the second fork"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 5.*New value = 6.*after-fork2-A.*" "watchpoint A after the second fork"
+    gdb_test "continue" \
+	     "atchpoint \[0-9\]+: var.*Old value = 6.*New value = 7.*after-fork2-B.*" "watchpoint B after the second fork"
+    gdb_test "continue" "Continuing\\..*\r\nBreakpoint \[0-9\]+, mark_exit .*" "finish"
+
+
+    # cleanup
+    set pf_prefix $prefix_test
+}
+
+test parent FOLLOW_PARENT
+
+# Only GNU/Linux is known to support `set follow-fork-mode child'.
+if [istarget "*-*-linux*"] {
+    test child FOLLOW_CHILD
+} else {
+    untested "${testfile}: child"
+}
diff --git a/gdb/testsuite/gdb.threads/watchpoint-fork.h b/gdb/testsuite/gdb.threads/watchpoint-fork.h
new file mode 100644
index 0000000..cb109fa
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/watchpoint-fork.h
@@ -0,0 +1,32 @@
+/* Test case for forgotten hw-watchpoints after fork()-off of a process.
+
+   Copyright 2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifdef THREAD
+#include <pthread.h>
+
+extern volatile int step;
+extern pthread_t thread;
+#endif /* THREAD */
+
+extern volatile int var;
+
+extern void marker (void);
+extern void forkoff (int nr);