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[media] cx88: Fix unsafe locking in suspend-resume

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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>
This commit is contained in:
Alexey Khoroshilov 2013-04-13 18:52:04 -03:00 committed by Mauro Carvalho Chehab
parent cdcfe40a5f
commit 5ddfbbb9ca
2 changed files with 12 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
drivers/media/pci/cx88/cx88-mpeg.c
View file

@ -532,16 +532,17 @@ static int cx8802_suspend_common(struct pci_dev *pci_dev, pm_message_t state)
{
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 @@ static int cx8802_resume_common(struct pci_dev *pci_dev)
{
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 @@ static int cx8802_resume_common(struct pci_dev *pci_dev)
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;
}

10
drivers/media/pci/cx88/cx88-video.c
View file

@ -1954,9 +1954,10 @@ static int cx8800_suspend(struct pci_dev *pci_dev, pm_message_t state)
{
struct cx8800_dev *dev = pci_get_drvdata(pci_dev);
struct cx88_core *core = dev->core;
unsigned long flags;
/* stop video+vbi capture */
spin_lock(&dev->slock);
spin_lock_irqsave(&dev->slock, flags);
if (!list_empty(&dev->vidq.active)) {
printk("%s/0: suspend video\n", core->name);
stop_video_dma(dev);
@ -1967,7 +1968,7 @@ static int cx8800_suspend(struct pci_dev *pci_dev, pm_message_t state)
cx8800_stop_vbi_dma(dev);
del_timer(&dev->vbiq.timeout);
}
spin_unlock(&dev->slock);
spin_unlock_irqrestore(&dev->slock, flags);
if (core->ir)
cx88_ir_stop(core);
@ -1986,6 +1987,7 @@ static int cx8800_resume(struct pci_dev *pci_dev)
{
struct cx8800_dev *dev = pci_get_drvdata(pci_dev);
struct cx88_core *core = dev->core;
unsigned long flags;
int err;
if (dev->state.disabled) {
@ -2016,7 +2018,7 @@ static int cx8800_resume(struct pci_dev *pci_dev)
cx_set(MO_PCI_INTMSK, core->pci_irqmask);
/* restart video+vbi capture */
spin_lock(&dev->slock);
spin_lock_irqsave(&dev->slock, flags);
if (!list_empty(&dev->vidq.active)) {
printk("%s/0: resume video\n", core->name);
restart_video_queue(dev,&dev->vidq);
@ -2025,7 +2027,7 @@ static int cx8800_resume(struct pci_dev *pci_dev)
printk("%s/0: resume vbi\n", core->name);
cx8800_restart_vbi_queue(dev,&dev->vbiq);
}
spin_unlock(&dev->slock);
spin_unlock_irqrestore(&dev->slock, flags);
return 0;
}