[patch 026/100] V4L/DVB (10943): cx88: Prevent general protection fault on rmmod

Chris Wright
2009-04-23T07:33:04Z

[-- Attachment #1: v4l-dvb-cx88-prevent-general-protection-fault-on-rmmod.patch --]
[-- Type: text/plain, Size: 2262 bytes --]

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

From: Jean Delvare <khali@linux-fr.org>

upstream commit: 569b7ec73abf576f9a9e4070d213aadf2cce73cb

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.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
---
drivers/media/video/cx88/cx88-input.c | 25 +++++++------------------
1 file changed, 7 insertions(+), 18 deletions(-)

--- a/drivers/media/video/cx88/cx88-input.c
+++ b/drivers/media/video/cx88/cx88-input.c
@@ -48,8 +48,7 @@ struct cx88_IR {

/* poll external decoder */
int polling;
- struct work_struct work;
- struct timer_list timer;
+ struct delayed_work work;
u32 gpio_addr;
u32 last_gpio;
u32 mask_keycode;
@@ -143,27 +142,19 @@ static void cx88_ir_handle_key(struct cx
}
}

-static void ir_timer(unsigned long data)
-{
- struct cx88_IR *ir = (struct cx88_IR *)data;
-
- schedule_work(&ir->work);
-}
-
static void cx88_ir_work(struct work_struct *work)
{
- struct cx88_IR *ir = container_of(work, struct cx88_IR, work);
+ struct cx88_IR *ir = container_of(work, struct cx88_IR, work.work);

cx88_ir_handle_key(ir);
- mod_timer(&ir->timer, jiffies + msecs_to_jiffies(ir->polling));
+ schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));
}

void cx88_ir_start(struct cx88_core *core, struct cx88_IR *ir)
{
if (ir->polling) {
- setup_timer(&ir->timer, ir_timer, (unsigned long)ir);
- INIT_WORK(&ir->work, cx88_ir_work);
- schedule_work(&ir->work);
+ INIT_DELAYED_WORK(&ir->work, cx88_ir_work);
+ schedule_delayed_work(&ir->work, 0);
}
if (ir->sampling) {
core->pci_irqmask |= PCI_INT_IR_SMPINT;
@@ -179,10 +170,8 @@ void cx88_ir_stop(struct cx88_core *core
core->pci_irqmask &= ~PCI_INT_IR_SMPINT;
}

- if (ir->polling) {
- del_timer_sync(&ir->timer);
- flush_scheduled_work();
- }
+ if (ir->polling)
+ cancel_delayed_work_sync(&ir->work);
}

/* ---------------------------------------------------------------------- */