Re: PROBLEM: Kernel Bug on USB unplugging (Elo TouchSystems CarrollTouch 4500U)

[Oliver Neukum]

On Mon, 2016-05-30 at 18:47 +0200, Pierre Sauter wrote:
> On unplugging this USB Touchscreen, everytime I get either:
> 
> [  161.596055] BUG: unable to handle kernel NULL pointer dereference at 00000015
> [  161.596093] IP: [<c10c92b0>] get_next_timer_interrupt+0x80/0x270
> or
> [  155.892061] BUG: unable to handle kernel paging request at 30303046
> [  155.892101] IP: [<c10d13da>] get_next_timer_interrupt+0x8a/0x290
> 
> and then panic and the system is unresponsive.

Please try the attached patch.

	Regards
		Oliver

From 50a2b0b9e53cae8c4d608e672dd3db93673bd350 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@xxxxxxxx>
Date: Tue, 31 May 2016 10:08:47 +0200
Subject: [PATCH] hid-elo: kill not flush the work

Flushing a work that reschedules itself is not a sensible
operation. It needs to be killed.

Signed-off-by: Oliver Neukum <ONeukum@xxxxxxxx>
---
 drivers/hid/hid-elo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-elo.c b/drivers/hid/hid-elo.c
index aad8c16..0cd4f72 100644
--- a/drivers/hid/hid-elo.c
+++ b/drivers/hid/hid-elo.c
@@ -261,7 +261,7 @@ static void elo_remove(struct hid_device *hdev)
 	struct elo_priv *priv = hid_get_drvdata(hdev);
 
 	hid_hw_stop(hdev);
-	flush_workqueue(wq);
+	cancel_delayed_work_sync(&priv->work);
 	kfree(priv);
 }
 
-- 
2.1.4