Patch "staging: comedi: jr3_pci: cope with jiffies wraparound" has been added to the 4.9-stable tree

Patch "staging: comedi: jr3_pci: cope with jiffies wraparound" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    staging: comedi: jr3_pci: cope with jiffies wraparound

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     staging-comedi-jr3_pci-cope-with-jiffies-wraparound.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 8ec04a491825e08068e92bed0bba7821893b6433 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@mev.co.uk>
Date: Fri, 17 Feb 2017 11:09:09 +0000
Subject: staging: comedi: jr3_pci: cope with jiffies wraparound

From: Ian Abbott <abbotti@mev.co.uk>

commit 8ec04a491825e08068e92bed0bba7821893b6433 upstream.

The timer expiry routine `jr3_pci_poll_dev()` checks for expiry by
checking whether the absolute value of `jiffies` (stored in local
variable `now`) is greater than the expected expiry time in jiffy units.
This will fail when `jiffies` wraps around.  Also, it seems to make
sense to handle the expiry one jiffy earlier than the current test.  Use
`time_after_eq()` to check for expiry.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/comedi/drivers/jr3_pci.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/comedi/drivers/jr3_pci.c
+++ b/drivers/staging/comedi/drivers/jr3_pci.c
@@ -611,7 +611,7 @@ static void jr3_pci_poll_dev(unsigned lo
 		s = &dev->subdevices[i];
 		spriv = s->private;
 
-		if (now > spriv->next_time_min) {
+		if (time_after_eq(now, spriv->next_time_min)) {
 			struct jr3_pci_poll_delay sub_delay;
 
 			sub_delay = jr3_pci_poll_subdevice(s);


Patches currently in stable-queue which might be from abbotti@mev.co.uk are

queue-4.9/staging-comedi-jr3_pci-fix-possible-null-pointer-dereference.patch
queue-4.9/staging-comedi-jr3_pci-cope-with-jiffies-wraparound.patch