linux-kernel - [142/244] floppy: use del_timer

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Date:	Wed, 28 Sep 2011 15:01:46 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Carsten Emde <C.Emde@...dl.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jens Axboe <axboe@...nel.dk>
Subject: [142/244] floppy: use del_timer_sync() in init cleanup

3.0-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Carsten Emde <C.Emde@...dl.org>

commit 6c4867f6469964e34c5f4ee229a2a7f71a34c7ff upstream.

When no floppy is found the module code can be released while a timer
function is pending or about to be executed.

CPU0                                  CPU1
				      floppy_init()
timer_softirq()
   spin_lock_irq(&base->lock);
   detach_timer();
   spin_unlock_irq(&base->lock);
   -> Interrupt
					del_timer();
				        return -ENODEV;
                                      module_cleanup();
   <- EOI
   call_timer_fn();
   OOPS

Use del_timer_sync() to prevent this.

Signed-off-by: Carsten Emde <C.Emde@...dl.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/block/floppy.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4250,7 +4250,7 @@ static int __init floppy_init(void)
 	use_virtual_dma = can_use_virtual_dma & 1;
 	fdc_state[0].address = FDC1;
 	if (fdc_state[0].address == -1) {
-		del_timer(&fd_timeout);
+		del_timer_sync(&fd_timeout);
 		err = -ENODEV;
 		goto out_unreg_region;
 	}
@@ -4261,7 +4261,7 @@ static int __init floppy_init(void)
 	fdc = 0;		/* reset fdc in case of unexpected interrupt */
 	err = floppy_grab_irq_and_dma();
 	if (err) {
-		del_timer(&fd_timeout);
+		del_timer_sync(&fd_timeout);
 		err = -EBUSY;
 		goto out_unreg_region;
 	}
@@ -4318,7 +4318,7 @@ static int __init floppy_init(void)
 		user_reset_fdc(-1, FD_RESET_ALWAYS, false);
 	}
 	fdc = 0;
-	del_timer(&fd_timeout);
+	del_timer_sync(&fd_timeout);
 	current_drive = 0;
 	initialized = true;
 	if (have_no_fdc) {
@@ -4368,7 +4368,7 @@ out_unreg_blkdev:
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 out_put_disk:
 	while (dr--) {
-		del_timer(&motor_off_timer[dr]);
+		del_timer_sync(&motor_off_timer[dr]);
 		if (disks[dr]->queue)
 			blk_cleanup_queue(disks[dr]->queue);
 		put_disk(disks[dr]);


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