[PATCH] show_task() fix and cleanup

show_task() is preinting negative numbers for free stack due to arithmetic
against the wrong pointer.

Fix that up, and clean up a few related things.

show_task still has bogus code which atempts to work out how much stack the
task has ever used - it cannot work because we don't actually zero out the
stack pages when allocating them.  We should fix that, or take it out.

include/linux/sched.h

@@ -151,6 +151,7 @@ extern void init_idle(task_t *idle, int cpu);
 
 extern void show_state(void);
 extern void show_regs(struct pt_regs *);
+extern void show_trace_task(task_t *tsk);
 
 /*
  * TASK is a pointer to the task whose backtrace we want to see (or NULL for current

kernel/sched.c

@@ -2569,17 +2569,16 @@ static inline struct task_struct *younger_sibling(struct task_struct *p)
 
 static void show_task(task_t * p)
 {
-	unsigned long free = 0;
 	task_t *relative;
-	int state;
-	static const char * stat_nam[] = { "R", "S", "D", "T", "Z", "W" };
+	unsigned state;
+	static const char *stat_nam[] = { "R", "S", "D", "T", "Z", "W" };
 
 	printk("%-13.13s ", p->comm);
 	state = p->state ? __ffs(p->state) + 1 : 0;
-	if (((unsigned) state) < sizeof(stat_nam)/sizeof(char *))
+	if (state < ARRAY_SIZE(stat_nam))
 		printk(stat_nam[state]);
 	else
-		printk(" ");
+		printk("?");
 #if (BITS_PER_LONG == 32)
 	if (p == current)
 		printk(" current  ");
@@ -2591,13 +2590,7 @@ static void show_task(task_t * p)
 	else
 		printk(" %016lx ", thread_saved_pc(p));
 #endif
-	{
-		unsigned long * n = (unsigned long *) (p->thread_info+1);
-		while (!*n)
-			n++;
-		free = (unsigned long) n - (unsigned long)(p->thread_info+1);
-	}
-	printk("%5lu %5d %6d ", free, p->pid, p->parent->pid);
+	printk("%5d %6d ", p->pid, p->parent->pid);
 	if ((relative = eldest_child(p)))
 		printk("%5d ", relative->pid);
 	else
@@ -2624,12 +2617,12 @@ void show_state(void)
 
 #if (BITS_PER_LONG == 32)
 	printk("\n"
-	       "                         free                        sibling\n");
-	printk("  task             PC    stack   pid father child younger older\n");
+	       "                                               sibling\n");
+	printk("  task             PC      pid father child younger older\n");
 #else
 	printk("\n"
-	       "                                 free                        sibling\n");
-	printk("  task                 PC        stack   pid father child younger older\n");
+	       "                                                       sibling\n");
+	printk("  task                 PC          pid father child younger older\n");
 #endif
 	read_lock(&tasklist_lock);
 	do_each_thread(g, p) {