[PATCH] 2.5.3-pre6: deadlock

This patch fixes a potential deadlock in ppdev.

	* drivers/char/ppdev.c: Watch out for errors from
	parport_claim_or_block.
	* drivers/parport/share.c: Watch out for signals.
	* drivers/parport/ChangeLog: Updated.

drivers/char/ppdev.c

@@ -320,6 +320,7 @@ static int pp_ioctl(struct inode *inode, struct file *file,
 	case PPCLAIM:
 	    {
 		struct ieee1284_info *info;
+		int ret;
 
 		if (pp->flags & PP_CLAIMED) {
 			printk (KERN_DEBUG CHRDEV
@@ -335,7 +336,10 @@ static int pp_ioctl(struct inode *inode, struct file *file,
 			}
 		}
 
-		parport_claim_or_block (pp->pdev);
+		ret = parport_claim_or_block (pp->pdev);
+		if (ret < 0)
+			return ret;
+
 		pp->flags |= PP_CLAIMED;
 
 		/* For interrupt-reporting to work, we need to be

drivers/parport/ChangeLog

+2002-01-04  Tim Waugh  <twaugh@redhat.com>
+
+	* share.c (parport_claim_or_block): Sleep interruptibly to prevent
+	a possible deadlock.
+
 2002-01-13  Niels Kristian Bech Jensen  <nkbj@image.dk>
 
 	* parport_pc.c: Change some occurrences of frob_set_mode to

drivers/parport/share.c

@@ -1011,7 +1011,11 @@ int parport_claim_or_block(struct pardevice *dev)
 		/* If dev->waiting is clear now, an interrupt
 		   gave us the port and we would deadlock if we slept.  */
 		if (dev->waiting) {
-			sleep_on(&dev->wait_q);
+			interruptible_sleep_on (&dev->wait_q);
+			if (signal_pending (current)) {
+				restore_flags (flags);
+				return -EINTR;
+			}
 			r = 1;
 		} else {
 			r = 0;
@@ -1084,7 +1088,7 @@ void parport_release(struct pardevice *dev)
 		if (pd->waiting & 2) { /* sleeping in claim_or_block */
 			parport_claim(pd);
 			if (waitqueue_active(&pd->wait_q))
-				wake_up(&pd->wait_q);
+				wake_up_interruptible(&pd->wait_q);
 			return;
 		} else if (pd->wakeup) {
 			pd->wakeup(pd->private);