Remove ptrace.patch used for early 2.4 kernels for Totalview.

Moe noted in 2008 that this was not needed on recent kernels.
Eight years seems like enough time.

contribs/Makefile.am

@@ -5,7 +5,6 @@ EXTRA_DIST = \
 	make-3.81.slurm.patch	\
 	make-4.0.slurm.patch	\
 	mpich1.slurm.patch	\
-	ptrace.patch		\
 	sgather			\
 	skilling.c		\
 	sjstat			\

contribs/Makefile.in

@@ -465,7 +465,6 @@ EXTRA_DIST = \
 	make-3.81.slurm.patch	\
 	make-4.0.slurm.patch	\
 	mpich1.slurm.patch	\
-	ptrace.patch		\
 	sgather			\
 	skilling.c		\
 	sjstat			\

contribs/README

@@ -88,14 +88,6 @@ of the Slurm contribs distribution follows:
      User applications can link with this library to use Slurm's mpi/pmi2
      plugin.
 
-  ptrace.patch       [ Linux Kernel patch required to for TotalView use ]
-     0. This has been fixed on most recent Linux kernels. Older versions of
-     Linux may need this patch support TotalView.
-     1. gdb and other tools cannot attach to a stopped process. The wait that
-     follows the PTRACE_ATTACH will block indefinitely.
-     2. It is not possible to use PTRACE_DETACH to leave a process stopped,
-     because ptrace ignores SIGSTOPs sent by the tracing process.
-
   sgather            [ shell script ]
      Gather remote files from a job into a central location. Reverse of of
      sbcast command.

contribs/ptrace.patch

-<http://linux.llnl.gov/software/kernel/ptrace.html>
-
-The Linux kernels must implement ptrace semantics required by the TotalView
-debugger. In order to initiate a parallel job under debugger control, a
-resource manager or job launch utility must be able to start all tasks
-in a stopped state, notify TotalView, and then allow TotalView debugger
-servers to attach to all tasks. This functionality requires the ability to:
-
-    * Detach from a traced process and leave the process stopped
-    * Attach to a stopped process
-
-Most newer versions of the Linux kernel support this functionality. For
-some older Linux kernels, both of the above are impossible without the
-following patch by Vic Zandy:
-
-    * initial posting <http://seclists.org/linux-kernel/2001/Dec/5146.html>
-    * follow up <http://seclists.org/lists/linux-kernel/2002/Mar/4490.html>
-
-Further discussion of Vic's patch can be found in this thread
-<http://seclists.org/lists/linux-kernel/2003/Mar/4457.html>. The main
-objections to the patch seemed to be
-
-    * It causes a behavior change for ptrace()
-    * No apparent agreement on the "right" thing to do when attaching to
-      a stopped process.
-
-[Any Etnus or Quadrics references to patches available?]
-
-On a vanilla 2.6.4 kernel, the ptrace() test is able to accomplish part
-1 of the test (detaching from a process and leaving the process
-stopped), but part 2 (attaching to a stopped process) appears to still
-be failing.
-
-It is possible to workaround a failure of step 2. Technically, it is not
-the attach that hangs when doing a ptrace() of a stopped process, but
-the subsequent call to waitpid(). Since the process was already stopped,
-the waitpid() never returns. Perhaps Etnus has implemented a workaround
-for this behavior.
-
-Testing:
-
-The followinbg piece of test code can be used to verify that the proper
-functionality exists in the current kernel:
-
-testptrace.c  <http://linux.llnl.gov/software/kernel/testptrace.c>
-
-This test should succeed when run without any arguments.
-
-------------------------------------------------------------------------
-
-<http://www.seclists.org/lists/linux-kernel/202/Mar/4490.html>
-
-Linux Kernel: Re: [PATCH] ptrace on stopped processes (2.4)
-From: Vic Zandy@cs.wisc.edu
-Date: Mar 18 2002
-
-
-This is a repost of the ptrace patch to 2.4 kernels
-we've discussed in recent months.
-
-Since the last post, I have updated it to linux 2.4.18
-(no changes) and tested it with subterfuge and uml.
-
-Subterfuge seems to be unaffected.
-
-UML needs minor modifications; I've discussed them with
-Jeff Dike and (I believe) he is happy.
-
-I believe I have addressed everyone's concerns.
-
-The patch fixes these two bugs:
-
-    1. gdb and other tools cannot attach to a stopped
-    process. The wait that follows the PTRACE_ATTACH
-    will block indefinitely.
-
-    2. It is not possible to use PTRACE_DETACH to leave
-    a process stopped, because ptrace ignores SIGSTOPs
-    sent by the tracing process.
-
-Vic
-
---- /home/vic/p/linux-2.4.18.orig/kernel/ptrace.c Wed Mar 13 13:14:54 2002
-+++ /home/vic/p/linux-2.4.18/kernel/ptrace.c Mon Mar 18 21:58:11 2002
-@@ -54,6 +54,7 @@
- 
- int ptrace_attach(struct task_struct *task)
- {
-+ int stopped;
-         task_lock(task);
-         if (task->pid <= 1)
-                 goto bad;
-@@ -90,7 +91,13 @@
-         }
-         write_unlock_irq(&tasklist_lock);
- 
-+ stopped = (task->state == TASK_STOPPED);
-         send_sig(SIGSTOP, task, 1);
-+ /* If it was stopped when we got here,
-+ clear the pending SIGSTOP. */
-+ if (stopped)
-+ wake_up_process(task);
-+
-         return 0;
- 
- bad:
---- /home/vic/p/linux-2.4.18.orig/arch/i386/kernel/signal.c Wed Mar 13
-13:16:44 2002
-+++ /home/vic/p/linux-2.4.18/arch/i386/kernel/signal.c Wed Mar 13
-16:31:38 2002
-@@ -620,9 +620,9 @@
-                                 continue;
-                         current->exit_code = 0;
- 
-- /* The debugger continued. Ignore SIGSTOP. */
-- if (signr == SIGSTOP)
-- continue;
-+ /* The debugger continued. */
-+ if (signr == SIGSTOP && current->ptrace & PT_PTRACED)
-+ continue; /* ignore SIGSTOP */
- 
-                         /* Update the siginfo structure. Is this good? */
-                         if (signr != info.si_signo) {
--
-
-------------------------------------------------------------------------

src/slurmd/slurmstepd/pdebug.c

@@ -56,9 +56,7 @@ pdebug_trace_process(stepd_step_rec_t *job, pid_t pid)
 {
 	/*  If task to be debugged, wait for it to stop via
 	 *  child's ptrace(PTRACE_TRACEME), then SIGSTOP, and
-	 *  ptrace(PTRACE_DETACH). This requires a kernel patch,
-	 *  which you may already have in place for TotalView.
-	 *  If not, apply the kernel patch in contribs/ptrace.patch
+	 *  ptrace(PTRACE_DETACH).
 	 */
 
 	if (job->task_flags & TASK_PARALLEL_DEBUG) {