FAILED: patch "[PATCH] comedi: jr3_pci: Fix synchronous deletion of timer" failed to apply to 5.10-stable tree

FAILED: patch "[PATCH] comedi: jr3_pci: Fix synchronous deletion of timer" failed to apply to 5.10-stable tree

[gregkh]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 44d9b3f584c59a606b521e7274e658d5b866c699
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025042808-difficult-germicide-075a@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 44d9b3f584c59a606b521e7274e658d5b866c699 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@mev.co.uk>
Date: Tue, 15 Apr 2025 13:39:01 +0100
Subject: [PATCH] comedi: jr3_pci: Fix synchronous deletion of timer

When `jr3_pci_detach()` is called during device removal, it calls
`timer_delete_sync()` to stop the timer, but the timer expiry function
always reschedules the timer, so the synchronization is ineffective.

Call `timer_shutdown_sync()` instead.  It does not matter that the timer
expiry function pointer is cleared, because the device is being removed.

Fixes: 07b509e6584a5 ("Staging: comedi: add jr3_pci driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20250415123901.13483-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/drivers/jr3_pci.c b/drivers/comedi/drivers/jr3_pci.c
index cdc842b32bab..75dce1ff2419 100644
--- a/drivers/comedi/drivers/jr3_pci.c
+++ b/drivers/comedi/drivers/jr3_pci.c
@@ -758,7 +758,7 @@ static void jr3_pci_detach(struct comedi_device *dev)
 	struct jr3_pci_dev_private *devpriv = dev->private;
 
 	if (devpriv)
-		timer_delete_sync(&devpriv->timer);
+		timer_shutdown_sync(&devpriv->timer);
 
 	comedi_pci_detach(dev);
 }

[PATCH 5.10.y] comedi: jr3_pci: Fix synchronous deletion of timer

[Ian Abbott]

commit 44d9b3f584c59a606b521e7274e658d5b866c699 upstream.

When `jr3_pci_detach()` is called during device removal, it calls
`del_timer_sync()` to stop the timer, but the timer expiry function
always reschedules the timer, so the synchronization is ineffective.

Add a member `bool timer_enable` to the device private data to indicate
whether the timer should be restarted.  Use the main comedi device
spin-lock for synchronization, as that is already used by the timer
expiry function.  (The upstream commit called `timer_shutdown_sync()`
instead of `del_timer_sync()`, but that is not available.)

Fixes: 07b509e6584a5 ("Staging: comedi: add jr3_pci driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20250415123901.13483-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/comedi/drivers/jr3_pci.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/comedi/drivers/jr3_pci.c b/drivers/staging/comedi/drivers/jr3_pci.c
index 7a02c4fa3cda..cc1232609f32 100644
--- a/drivers/staging/comedi/drivers/jr3_pci.c
+++ b/drivers/staging/comedi/drivers/jr3_pci.c
@@ -88,6 +88,7 @@ struct jr3_pci_poll_delay {
 struct jr3_pci_dev_private {
 	struct timer_list timer;
 	struct comedi_device *dev;
+	bool timer_enable;
 };
 
 union jr3_pci_single_range {
@@ -612,10 +613,11 @@ static void jr3_pci_poll_dev(struct timer_list *t)
 				delay = sub_delay.max;
 		}
 	}
+	if (devpriv->timer_enable) {
+		devpriv->timer.expires = jiffies + msecs_to_jiffies(delay);
+		add_timer(&devpriv->timer);
+	}
 	spin_unlock_irqrestore(&dev->spinlock, flags);
-
-	devpriv->timer.expires = jiffies + msecs_to_jiffies(delay);
-	add_timer(&devpriv->timer);
 }
 
 static struct jr3_pci_subdev_private *
@@ -764,6 +766,7 @@ static int jr3_pci_auto_attach(struct comedi_device *dev,
 	devpriv->dev = dev;
 	timer_setup(&devpriv->timer, jr3_pci_poll_dev, 0);
 	devpriv->timer.expires = jiffies + msecs_to_jiffies(1000);
+	devpriv->timer_enable = true;
 	add_timer(&devpriv->timer);
 
 	return 0;
@@ -773,8 +776,12 @@ static void jr3_pci_detach(struct comedi_device *dev)
 {
 	struct jr3_pci_dev_private *devpriv = dev->private;
 
-	if (devpriv)
+	if (devpriv) {
+		spin_lock_bh(&dev->spinlock);
+		devpriv->timer_enable = false;
+		spin_unlock_bh(&dev->spinlock);
 		del_timer_sync(&devpriv->timer);
+	}
 
 	comedi_pci_detach(dev);
 }
-- 
2.47.2

Re: [PATCH 5.10.y] comedi: jr3_pci: Fix synchronous deletion of timer

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 44d9b3f584c59a606b521e7274e658d5b866c699

Status in newer kernel trees:
6.14.y | Not found
6.12.y | Not found
6.6.y | Not found
6.1.y | Not found
5.15.y | Not found

Note: The patch differs from the upstream commit:
---
1:  44d9b3f584c59 < -:  ------------- comedi: jr3_pci: Fix synchronous deletion of timer
-:  ------------- > 1:  0cd4caf40f329 comedi: jr3_pci: Fix synchronous deletion of timer
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.10.y       |  Success    |  Success   |