gdb/gdb-6.5-attach-stop.patch

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=209521
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=219118
http://sources.redhat.com/ml/gdb-patches/2006-09/msg00092.html

Specific to Red Hat kernels, kernel.org kernels lockup on gdb "attach".


2006-12-11  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb-6.5/gdb/linux-nat.c (linux_nat_attach): Handle already stopped
	processes, compiled either in a nonthreaded or a threaded mode.

2006-12-11  Jeff Johnston  <jjohnstn@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.base/attachstop.exp, gdb.base/attachstop.c: New files,
	test attaching to already stopped processes, compiled either in
	a nonthreaded or a threaded mode.


diff -u -ruNp gdb-6.5-orig/gdb/linux-nat.c gdb-6.5/gdb/linux-nat.c
--- gdb-6.5-orig/gdb/linux-nat.c	2006-12-12 00:30:18.000000000 +0100
+++ gdb-6.5/gdb/linux-nat.c	2006-12-11 23:42:23.000000000 +0100
@@ -567,7 +567,9 @@ linux_handle_extended_wait (int pid, int
 	  else if (ret != new_pid)
 	    internal_error (__FILE__, __LINE__,
 			    _("wait returned unexpected PID %d"), ret);
-	  else if (!WIFSTOPPED (status) || WSTOPSIG (status) != SIGSTOP)
+	  /* In some cases we get 0 for the `SIGSTOP' signal.  */
+	  else if (!WIFSTOPPED (status) ||
+		   (WSTOPSIG (status) != SIGSTOP && WSTOPSIG (status) != 0))
 	    internal_error (__FILE__, __LINE__,
 			    _("wait returned unexpected status 0x%x"), status);
 	}
@@ -1007,8 +1009,9 @@ lin_lwp_attach_lwp (ptid_t ptid, int ver
 	  lp->cloned = 1;
 	}
 
+      /* In some cases we get 0 for the `SIGSTOP' signal.  */
       gdb_assert (pid == GET_LWP (ptid)
-		  && WIFSTOPPED (status) && WSTOPSIG (status));
+		  && WIFSTOPPED (status));
 
       target_post_attach (pid);
 
@@ -1062,13 +1065,14 @@ linux_nat_attach (char *args, int from_t
       lp->cloned = 1;
     }
 
-  gdb_assert (pid == GET_PID (inferior_ptid)
-	      && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP);
+  /* In some cases we get 0 for the `SIGSTOP' signal.  */
+  gdb_assert (pid == GET_PID (inferior_ptid) && WIFSTOPPED (status)
+              && (WSTOPSIG (status) == SIGSTOP || WSTOPSIG (status) == 0));
 
   lp->stopped = 1;
 
-  /* Fake the SIGSTOP that core GDB expects.  */
-  lp->status = W_STOPCODE (SIGSTOP);
+  /* Provide the stop status that core GDB expects.  */
+  lp->status = status;
   lp->resumed = 1;
   if (debug_linux_nat)
     {
@@ -1509,7 +1513,8 @@ stop_wait_callback (struct lwp_info *lp,
 	  return stop_wait_callback (lp, flush_mask);
 	}
 
-      if (WSTOPSIG (status) != SIGSTOP)
+      /* In some cases we get 0 for the `SIGSTOP' signal.  */
+      if (WSTOPSIG (status) != SIGSTOP && WSTOPSIG (status) != 0)
 	{
 	  if (WSTOPSIG (status) == SIGTRAP)
 	    {
@@ -2093,8 +2098,10 @@ retry:
 	      if (options & __WCLONE)
 		lp->cloned = 1;
 
+	      /* In some cases we get 0 for the `SIGSTOP' signal.  */
 	      gdb_assert (WIFSTOPPED (status)
-			  && WSTOPSIG (status) == SIGSTOP);
+			  && (WSTOPSIG (status) == SIGSTOP
+			      || WSTOPSIG (status) == 0));
 	      lp->signalled = 1;
 
 	      if (!in_thread_list (inferior_ptid))
@@ -2195,8 +2202,10 @@ retry:
 	  /* Make sure we don't report a SIGSTOP that we sent
 	     ourselves in an attempt to stop an LWP, unless we
 	     intentionally want to see the SIGSTOP.  */
+	  /* In some cases we get 0 for the `SIGSTOP' signal.  */
 	  if (lp->signalled && !intentional_stop
-	      && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
+	      && WIFSTOPPED (status) && (WSTOPSIG (status) == SIGSTOP
+					 || WSTOPSIG (status) == 0))
 	    {
 	      if (debug_linux_nat)
 		fprintf_unfiltered (gdb_stdlog,
diff -u -ruNp gdb-6.5-orig/gdb/testsuite/gdb.base/attachstop.c gdb-6.5/gdb/testsuite/gdb.base/attachstop.c
--- gdb-6.5-orig/gdb/testsuite/gdb.base/attachstop.c	1970-01-01 01:00:00.000000000 +0100
+++ gdb-6.5/gdb/testsuite/gdb.base/attachstop.c	2006-12-11 23:58:22.000000000 +0100
@@ -0,0 +1,51 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2005 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 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. */
+
+/* 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;
+}
diff -u -ruNp gdb-6.5-orig/gdb/testsuite/gdb.base/attachstop.exp gdb-6.5/gdb/testsuite/gdb.base/attachstop.exp
--- gdb-6.5-orig/gdb/testsuite/gdb.base/attachstop.exp	1970-01-01 01:00:00.000000000 +0100
+++ gdb-6.5/gdb/testsuite/gdb.base/attachstop.exp	2006-12-12 00:26:39.000000000 +0100
@@ -0,0 +1,234 @@
+# Copyright 2005-2006
+
+# 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.
+
+# 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>.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+# This test only works on Linux
+if { ![istarget "*-*-linux-gnu*"] } {
+    return 0
+}
+
+set testfile "attachstop"
+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 &]
+    exec 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 ${binfile}
+
+    # Verify that we can attach to the process by first giving its
+    # executable name via the file command, and using attach with the
+    # process ID.
+
+    set test "$threadtype: set file, before attach1 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 "$threadtype: attach1 to stopped, after setting file"
+    gdb_test_multiple "attach $testpid" "$test" {
+	-re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+	    pass "$test"
+	}
+    }
+
+    if {[string equal $threadtype threaded]} {
+	gdb_test "thread apply all bt" ".*sleep.*clone.*" "$threadtype: attach1 to stopped bt"
+    } else {
+	gdb_test "bt" ".*sleep.*main.*" "$threadtype: attach1 to stopped bt"
+    }
+
+    # Exit and detach the process.
+       
+    gdb_exit
+
+    set fileid [open /proc/${testpid}/status r];
+    gets $fileid line1;
+    gets $fileid line2;
+    close $fileid;
+
+    set test "$threadtype: attach1, exit leaves process stopped"
+    if {[string match "*(stopped)*" $line2]} {
+      pass $test
+    } else {
+      fail $test
+    }
+
+    # At this point, the process should still be stopped
+
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+    gdb_load ${binfile}
+
+    # Verify that we can attach to the process just by giving the
+    # process ID.
+       
+    set test "$threadtype: attach2 to stopped, after setting file"
+    gdb_test_multiple "attach $testpid" "$test" {
+	-re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $" {
+	    pass "$test"
+	}
+    }
+
+    if {[string equal $threadtype threaded]} {
+	gdb_test "thread apply all bt" ".*sleep.*clone.*" "$threadtype: attach2 to stopped bt"
+    } else {
+	gdb_test "bt" ".*sleep.*main.*" "$threadtype: attach2 to stopped bt"
+    }
+    gdb_breakpoint [gdb_get_line_number "$threadtype: 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 unbreakable interrupt"
+    gdb_expect 4 {
+      -re "Program received signal SIGINT.*$gdb_prompt $"
+	{
+	  fail "$test (broke into)"
+	}
+      -re "Breakpoint \[0-9\].*$srcfile.*$gdb_prompt $"
+	{
+	  fail "$test (broke into)"
+	}
+      timeout
+	{
+	  pass $test
+	}
+    }
+
+    # Continue the program 
+    remote_exec build "kill -s CONT ${testpid}"
+
+    if {[string equal $threadtype threaded]} {
+	# Isn't a bug? kernel-xen-2.6.18-1.2767.el5.i686
+        set signal_expect "SIGCONT"
+    } else {
+    	set signal_expect "SIGINT"
+    }
+    # Already sent before: after 1000 {send_gdb "\003"}
+    set test "$threadtype: attach2 stop by interrupt"
+    gdb_expect {
+      -re "Program received signal $signal_expect,.*$gdb_prompt $"
+	{
+	  pass $test
+	}
+      -re "Breakpoint \[0-9\].*$srcfile.*$gdb_prompt $"
+	{
+	  pass $test
+	}
+      timeout
+	{
+	  fail "$test (timeout)"
+	}
+    }
+
+    gdb_exit
+
+    # Avoid some race:
+    exec sleep 2
+
+    # At this point, the process should be sleeping
+
+    set fileid2 [open /proc/${testpid}/status r];
+    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