[media] cx88: Fix unsafe locking in suspend-resume
Legacy PCI suspend-resume handlers are called with interrupts enabled.
But cx8800_suspend/cx8800_resume and
cx8802_suspend_common/cx8802_resume_common use spin_lock/spin_unlock
functions to acquire dev->slock, while the same lock is acquired in the
corresponding irq-handlers: cx8800_irq and cx8802_irq.
That means a deadlock is possible if an interrupt happens while suspend
or resume owns the lock. The patch replaces spin_lock/spin_unlock with
spin_lock_irqsave/spin_unlock_irqrestore.
Found by Linux Driver Verification project (linuxtesting.org).
[mchehab@redhat.com: Fix CodingStyle]
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/pci/cx88/cx88-mpeg.c b/drivers/media/pci/cx88/cx88-mpeg.c
index c9d3182..2d3507e 100644
--- a/drivers/media/pci/cx88/cx88-mpeg.c
+++ b/drivers/media/pci/cx88/cx88-mpeg.c
@@ -532,16 +532,17 @@
{
struct cx8802_dev *dev = pci_get_drvdata(pci_dev);
struct cx88_core *core = dev->core;
+ unsigned long flags;
/* stop mpeg dma */
- spin_lock(&dev->slock);
+ spin_lock_irqsave(&dev->slock, flags);
if (!list_empty(&dev->mpegq.active)) {
dprintk( 2, "suspend\n" );
printk("%s: suspend mpeg\n", core->name);
cx8802_stop_dma(dev);
del_timer(&dev->mpegq.timeout);
}
- spin_unlock(&dev->slock);
+ spin_unlock_irqrestore(&dev->slock, flags);
/* FIXME -- shutdown device */
cx88_shutdown(dev->core);
@@ -558,6 +559,7 @@
{
struct cx8802_dev *dev = pci_get_drvdata(pci_dev);
struct cx88_core *core = dev->core;
+ unsigned long flags;
int err;
if (dev->state.disabled) {
@@ -584,12 +586,12 @@
cx88_reset(dev->core);
/* restart video+vbi capture */
- spin_lock(&dev->slock);
+ spin_lock_irqsave(&dev->slock, flags);
if (!list_empty(&dev->mpegq.active)) {
printk("%s: resume mpeg\n", core->name);
cx8802_restart_queue(dev,&dev->mpegq);
}
- spin_unlock(&dev->slock);
+ spin_unlock_irqrestore(&dev->slock, flags);
return 0;
}