diff mbox

cx88: Prevent general protection fault on rmmod

Message ID 20090305103824.351d0110@hyperion.delvare (mailing list archive)
State Accepted
Headers show

Commit Message

Jean Delvare March 5, 2009, 9:38 a.m. UTC 
From: Jean Delvare <khali@linux-fr.org>
Subject: cx88: Prevent general protection fault on rmmod

When unloading the cx8800 driver I sometimes get a general protection
fault. Analysis revealed a race in cx88_ir_stop(). It can be solved by
using a delayed work instead of a timer for infrared input polling.

This fixes kernel.org bug #12802.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
---
 linux/drivers/media/video/cx88/cx88-input.c |   25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

Comments

Trent Piepho March 5, 2009, 9:43 a.m. UTC | #1 
On Thu, 5 Mar 2009, Jean Delvare wrote:
> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
>  	struct work_struct work;
>  	struct timer_list timer;
> +#else
> +	struct delayed_work work;
> +#endif

You don't need this compat stuff.  compat.h will take are of it for you.
Just code it like you would for the latest kernel.  The only thing you need
to worry about is the way the third argument of the work function went
away, but the ifdef that's already there takes care of it.
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Jean Delvare March 5, 2009, 1:48 p.m. UTC | #2 
On Thu, 5 Mar 2009 01:43:55 -0800 (PST), Trent Piepho wrote:
> On Thu, 5 Mar 2009, Jean Delvare wrote:
> > +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
> >  	struct work_struct work;
> >  	struct timer_list timer;
> > +#else
> > +	struct delayed_work work;
> > +#endif
> 
> You don't need this compat stuff.  compat.h will take are of it for you.
> Just code it like you would for the latest kernel.  The only thing you need
> to worry about is the way the third argument of the work function went
> away, but the ifdef that's already there takes care of it.

OK, thanks. I'll resend updated patches soon.
diff mbox

Patch

--- v4l-dvb.orig/linux/drivers/media/video/cx88/cx88-input.c	2009-03-04 09:52:20.000000000 +0100
+++ v4l-dvb/linux/drivers/media/video/cx88/cx88-input.c	2009-03-04 19:03:17.000000000 +0100
@@ -49,8 +49,12 @@  struct cx88_IR {
 
 	/* poll external decoder */
 	int polling;
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
 	struct work_struct work;
 	struct timer_list timer;
+#else
+	struct delayed_work work;
+#endif
 	u32 gpio_addr;
 	u32 last_gpio;
 	u32 mask_keycode;
@@ -144,6 +148,7 @@  static void cx88_ir_handle_key(struct cx
 	}
 }
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
 static void ir_timer(unsigned long data)
 {
 	struct cx88_IR *ir = (struct cx88_IR *)data;
@@ -151,7 +156,6 @@  static void ir_timer(unsigned long data)
 	schedule_work(&ir->work);
 }
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
 static void cx88_ir_work(void *data)
 #else
 static void cx88_ir_work(struct work_struct *work)
@@ -160,23 +164,30 @@  static void cx88_ir_work(struct work_str
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
 	struct cx88_IR *ir = data;
 #else
-	struct cx88_IR *ir = container_of(work, struct cx88_IR, work);
+	struct delayed_work *dwork = container_of(work, struct delayed_work,
+						  work);
+	struct cx88_IR *ir = container_of(dwork, struct cx88_IR, work);
 #endif
 
 	cx88_ir_handle_key(ir);
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
 	mod_timer(&ir->timer, jiffies + msecs_to_jiffies(ir->polling));
+#else
+	schedule_delayed_work(dwork, msecs_to_jiffies(ir->polling));
+#endif
 }
 
 void cx88_ir_start(struct cx88_core *core, struct cx88_IR *ir)
 {
 	if (ir->polling) {
-		setup_timer(&ir->timer, ir_timer, (unsigned long)ir);
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
+		setup_timer(&ir->timer, ir_timer, (unsigned long)ir);
 		INIT_WORK(&ir->work, cx88_ir_work, ir);
+		schedule_work(&ir->work);
 #else
-		INIT_WORK(&ir->work, cx88_ir_work);
+		INIT_DELAYED_WORK(&ir->work, cx88_ir_work);
+		schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));
 #endif
-		schedule_work(&ir->work);
 	}
 	if (ir->sampling) {
 		core->pci_irqmask |= PCI_INT_IR_SMPINT;
@@ -193,8 +204,12 @@  void cx88_ir_stop(struct cx88_core *core
 	}
 
 	if (ir->polling) {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
 		del_timer_sync(&ir->timer);
 		flush_scheduled_work();
+#else
+		cancel_delayed_work_sync(&ir->work);
+#endif
 	}
 }