[patch] Fix process freezing

[patch] Fix process freezing

[Pavel Machek]

If process freezing fails, some processes are frozen, and rest are
left in "were asked to be frozen" state. Thats wrong, we should leave
it in some consistent state.

Signed-off-by: Pavel Machek <pavel@suse.cz>

--- linux-mm/kernel/power/process.c	2005-08-24 20:25:11.000000000 +0200
+++ linux/kernel/power/process.c	2005-08-26 11:30:40.000000000 +0200
@@ -81,13 +81,33 @@
 		} while_each_thread(g, p);
 		read_unlock(&tasklist_lock);
 		yield();			/* Yield is okay here */
-		if (time_after(jiffies, start_time + TIMEOUT)) {
+		if (todo && time_after(jiffies, start_time + TIMEOUT)) {
 			printk( "\n" );
 			printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
-			return todo;
+			break;
 		}
 	} while(todo);
 
+	/* This does not unfreeze processes that are already frozen
+	 * (we have slightly ugly calling convention in that respect,
+	 * and caller must call thaw_processes() if something fails),
+	 * but it cleans up leftover PF_FREEZE requests.
+	 */
+	if (todo) {
+		read_lock(&tasklist_lock);
+		do_each_thread(g, p)
+			if (freezing(p)) {
+				pr_debug("  clean up: %s\n", p->comm);
+				p->flags &= ~PF_FREEZE;
+				spin_lock_irqsave(&p->sighand->siglock, flags);
+				recalc_sigpending_tsk(p);
+				spin_unlock_irqrestore(&p->sighand->siglock, flags);
+			}
+		while_each_thread(g, p);
+		read_unlock(&tasklist_lock);
+		return todo;
+	}
+
 	printk( "|\n" );
 	BUG_ON(in_atomic());
 	return 0;

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