[SSI] openssi/kernel/kernel exit.c,1.21,1.22 pid.c,1.9,1.10

Update of /cvsroot/ssic-linux/openssi/kernel/kernel
In directory sfp-cvsdas-3.v30.ch3.sourceforge.com:/tmp/cvs-serv23888/kernel

Modified Files:
      Tag: OPENSSI-FC
	exit.c pid.c 
Log Message:
VPROC:
- Fix select_bad_process() NULL p_vproc pointer dereference.
- Fix de_thread() related issues:
  - Fix de_thread() calling VPOP_RECLAIM_CHILD() while holding spin_lock(task->p
roc_lock). Code path might sleep.
  - Fix NULL p_vproc pointer dereference when thread group leader is exiting, ha
s PF_FORKNOEXEC flag, and has lost race with de_thread(). Affects exit_notify(),
 forget_original_parent(), and will_become_orphaned_pgrp(). When p_vproc is NULL
 the exiting process reaps itself.
  - Fix dpvproc_nocldwait_async_handler() NULL pointer dereference due to failed
 lookup for vproc of new parent when lost race with de_thread(). (#ifdef RELEASE
_TASK_LEADER_GONE__VPROC_FIX)
  - New PVPOP_SWITCH_PID() to switch VProc PID of process doing de_thread().
  - New PV_DETHREAD_REAP flag is set during de_thread() to indicate to child rea
per to reap thread group leader without delay.
  - Fix oops in do_notify_resume() path due to NULL pointer dereference. p_vproc
 is NULL after bad fork.

VPROC (#ifdef VPROC_RELEASE__REFCNT_RACE_FIX):
- Fix extra VPROC_RELE() on PVPOP_RMV_PGRP_LIST() -ESRCH error.
- Fix PVPOP_REAP() extra dpvproc_remove_pgrp_leader_member_care() on PVPOP_RMV_P
GRP_LIST() -EBUSY error; was typo in if-test.
- PVPOP_REAP() no longer does async PVPOP_RMV_PGRP_LIST(); now sync. Don't see h
ow reaping parent can hold PGRP LOCK in PVPOP_REAP() path.
- Fix exit_vproc() did not decrement vproc reference for process group leader on
 member node. This is in do_fork() error path.

VPROC (#ifdef VPROC_CONTINUE):
- Fix dpvproc_nocldwait_async_handler() deadlock on PVPOP_REAP() -EBUSY due to d
elay_group_leader(). PV_REAPER_RETRY flag is set and group leader is re-inserted
 into the queue so that the remaining threads in thread group can be reaped by t
his handler to remove the delay_group_leader() condition.
- Regression:
  - Fix pproc_reap() should succeed, but returns -EBUSY when process is a thread
 group leader in non-empty thread group and is already in EXIT_DEAD state.


Index: exit.c
===================================================================
RCS file: /cvsroot/ssic-linux/openssi/kernel/kernel/exit.c,v
retrieving revision 1.21
retrieving revision 1.22
diff -u -d -r1.21 -r1.22
--- exit.c	27 Oct 2009 03:18:30 -0000	1.21
+++ exit.c	17 Dec 2009 05:46:51 -0000	1.22
@@ -244,8 +244,10 @@
 	 */
 	if (ignored_task) {
 		v = ignored_task->p_vproc;
-		BUG_ON(!VP_HASHED(v));
-		(void) VPOP_ADJUST_JOB_CONTROL_COUNT(v);
+		if (v) {
+			BUG_ON(!VP_HASHED(v));
+			(void) VPOP_ADJUST_JOB_CONTROL_COUNT(v);
+		}
 		return 0;
 	}
 
@@ -747,7 +749,8 @@
 
 		/* release lock obtained in exit_notify() - dont reacquire */
 		write_unlock_irq(&tasklist_lock);
-		VPOP_REASSIGN_ORIGINAL_PARENT(father->p_vproc, newppid);
+		if (father->p_vproc)
+			VPOP_REASSIGN_ORIGINAL_PARENT(father->p_vproc, newppid);
 	}
 #else
 	list_for_each_safe(_p, _n, &father->children) {
@@ -904,11 +907,29 @@
 
 
 #ifdef CONFIG_VPROC
-	VPOP_CLEANUP_VPROC_RELATIONS(tsk->p_vproc);
+	/* TODO: Delay VPOP_XXX calls so we can hold
+	 * write_lock_irq(&tasklist_lock) throughout.
+	 */
+	if (tsk->p_vproc) {
+		VPOP_CLEANUP_VPROC_RELATIONS(tsk->p_vproc);
 #ifdef VPROC_PVP_CHILD_LL
-	WARN_ON(!list_empty(&PVP(tsk->p_vproc)->pvp_children));
+		WARN_ON(!list_empty(&PVP(tsk->p_vproc)->pvp_children));
 #endif
-#else
+	} else {
+		SSI_ASSERT(tsk->flags & PF_FORKNOEXEC);
+		tsk->exit_state = EXIT_DEAD;
+
+		/*
+		 * Clear these here so that update_process_times() won't try to deliver
+		 * itimer, profile or rlimit signals to this task while it is in late exit.
+		 */
+		tsk->it_virt_value = cputime_zero;
+		tsk->it_prof_value = cputime_zero;
+
+		/* release it - nobody will wait for it */
+		release_task(tsk);
+	}
+#else /* CONFIG_VPROC */
 	/* If something other than our normal parent is ptracing us, then
 	 * send it a SIGCHLD instead of honoring exit_signal.  exit_signal
 	 * only has special meaning to our real parent.
@@ -1747,11 +1768,26 @@
 	get_task_struct(tsk);
 	do {
 #ifdef TASK_HOLD_VPROC
+#ifdef VPROC_RCU_LIST
+		int retry = 0;
+retry_vproc:
+#endif
 		vp = tsk->p_vproc;
 
 		if (!VPROC_HOLD_AND_CHECK(vp, "do_wait")) {
+#ifdef VPROC_RCU_LIST
+			if (retry) {
+				put_task_struct(tsk);
+				goto next_thread;
+			}
+			/* de_thread() might be re-hashing vproc */
+			retry = 1;
+			idelay(HZ>>4);
+			goto retry_vproc;
+#else
 			put_task_struct(tsk);
 			goto next_thread;
+#endif
 		}
 
 		vrtn = VPOP_WAIT(vp, pid, vopts, stat_addr, &pusage, &vretval);
@@ -2189,24 +2225,43 @@
 	if (security_task_wait(cp))
 		goto out_unlock;
 
+#ifdef VPROC_CONTINUE
+	/* Perform some checks to ensure we don't unnecessarily
+	 * delay reaping the thread group leader.
+	 */
+	if (delayed_group_leader &&
+	    (vopts & VPROC_WZOMBIE)) {
+		/* FIXME: We don't want to reap before VPOP_RECLAIM_CHILD(leader)
+		 * completes in de_thread(). Also if switch_exec_pids() is run then
+		 * delayed_group_leader == 0.
+		 */
+		if (vopts & VPROC_WDETHREAD)
+			delayed_group_leader = 0;
+#if 0
+		/* From exit_notify(), reap self on group exit */
+		else if (cp->exit_signal == -1 &&
+		    (likely(cp->ptrace == 0) ||
+		     unlikely(cp->signal->flags & SIGNAL_GROUP_EXIT)))
+			delayed_group_leader = 0;
+#endif
+	}
+#else
 	if (vopts & VPROC_WZOMBIE) {
-		if (delayed_group_leader) { 
+		if (delayed_group_leader) {
 			/* Cannot be reaped yet, member list not empty yet */
 			retval = -EBUSY;
-#ifndef VPROC_CONTINUE
 			goto out_unlock;
 		}
 		/* Wait for task to finish exiting */
 		WAIT_EVENT(&cp->p_exiting);
-#else
-		}
 #if 0
 		else if (!(vopts & VPROC_WNOWAIT))
 			/* Wait for task to finish exiting */
 			WAIT_EVENT(&cp->p_exiting);
 #endif
-#endif /* VPROC_CONTINUE */
 	}
+#endif /* !VPROC_CONTINUE */
+
 	/*
 	 * Task is ready to be reaped, reap it.
 	 */
@@ -2245,8 +2300,10 @@
 			 * Eligible but we cannot release
 			 * it yet:
 			 */
-			if (delayed_group_leader)
+			if (delayed_group_leader) {
+				retval = -EBUSY;
 				goto check_continued;
+			}
 			retval = wait_task_zombie(cp, (vopts & VPROC_WNOWAIT),
 							NULL,
 							stat_addr, pusagep);

Index: pid.c
===================================================================
RCS file: /cvsroot/ssic-linux/openssi/kernel/kernel/pid.c,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -d -r1.9 -r1.10
--- pid.c	5 Nov 2009 07:33:38 -0000	1.9
+++ pid.c	17 Dec 2009 05:46:51 -0000	1.10
@@ -300,7 +300,7 @@
 	leader->pid = leader->tgid = thread->pid;
 	thread->pid = thread->tgid;
 #ifdef VPROC
-	/* NB: There is no need to switch vproc pids.
+	/* SSI_XXX: No need to switch vproc pids?
 	 * glibc tst-exec4 passes with no stale vproc handles.
 	 */
 #if 0
@@ -326,6 +326,11 @@
 	leader->p_vproc->vp_pid = leader->pid;
 	list_add_rcu(&leader->p_vproc->vp_list, &vproc_hash[VPROCPIDHASH(leader->pid)]);
 	VPROC_LIST_UNLOCK();
+
+	/* Update pvp_pgid so we can get to pgrp list from pvproc */
+	/* SSI_XXX: Locking for pvp_pgid */
+	PVP(thread->p_vproc)->pvp_pgid = leader->pid;
+	PVP(leader->p_vproc)->pvp_pgid = leader->pid;
 #endif
 #endif
 	leader->epid = thread->epid;


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