Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754567Ab3DMVw0 (ORCPT ); Sat, 13 Apr 2013 17:52:26 -0400 Received: from mail.ispras.ru ([83.149.199.45]:50006 "EHLO mail.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753788Ab3DMVwZ (ORCPT ); Sat, 13 Apr 2013 17:52:25 -0400 From: Alexey Khoroshilov To: Mauro Carvalho Chehab Cc: Alexey Khoroshilov , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org Subject: [PATCH] [media] cx88: Fix unsafe locking in suspend-resume Date: Sun, 14 Apr 2013 01:52:04 +0400 Message-Id: <1365889924-5570-1-git-send-email-khoroshilov@ispras.ru> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4249 Lines: 122 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). Signed-off-by: Alexey Khoroshilov --- drivers/media/pci/cx88/cx88-mpeg.c | 10 ++++++---- drivers/media/pci/cx88/cx88-video.c | 10 ++++++---- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/media/pci/cx88/cx88-mpeg.c b/drivers/media/pci/cx88/cx88-mpeg.c index c9d3182..c6cdbdb 100644 --- a/drivers/media/pci/cx88/cx88-mpeg.c +++ b/drivers/media/pci/cx88/cx88-mpeg.c @@ -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; } diff --git a/drivers/media/pci/cx88/cx88-video.c b/drivers/media/pci/cx88/cx88-video.c index bc78354..d72b403 100644 --- a/drivers/media/pci/cx88/cx88-video.c +++ b/drivers/media/pci/cx88/cx88-video.c @@ -1957,9 +1957,10 @@ 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); @@ -1970,7 +1971,7 @@ 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); @@ -1989,6 +1990,7 @@ 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) { @@ -2019,7 +2021,7 @@ 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); @@ -2028,7 +2030,7 @@ 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; } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/