usb: dwc3: omap: fix race of pm runtime with irq handler in probe

PATCH New Grygorii Strashko 2 participants 2 messages Dec 12, 2016

Subsystems (3)

USB DesignWare USB3 DRD IP driver OMAP USB support

lore

Share & tools

lore

Grygorii Strashko

author

2016-12-12 19:37 UTC #0 lore raw

PATCH v2 1/1 usb: dwc3: omap: fix race of pm runtime with irq handler in probe

Now races can happen between interrupt handler execution and PM runtime in error handling code path in probe and in dwc3_omap_remove() which will lead to system crash:

in probe:
...
err1:

	pm_runtime_put_sync(dev);
^^ PM runtime can race with IRQ handler when deferred probing happening
   due to extcon
	pm_runtime_disable(dev);

	return ret;

in dwc3_omap_remove:
...

	dwc3_omap_disable_irqs(omap);
^^ IRQs are disabled in HW, but handler may still run
	of_platform_depopulate(omap->dev);
	pm_runtime_put_sync(&pdev->dev);
^^ PM runtime can race with IRQ handler
	pm_runtime_disable(&pdev->dev);

	return 0;

So, OMAP DWC3 IRQ need to be disabled before calling pm_runtime_put() in probe and in dwc3_omap_remove().

Signed-off-by Grygorii Strashko <[email protected]>

---
Link on v1:
http://www.spinics.net/lists/linux-omap/msg133846.html

 drivers/usb/dwc3/dwc3-omap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

drivers/usb/dwc3/dwc3-omap.c +4 -2

index 29e80cc..eb1b9cb 100644
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/dwc3-omap.h>

@@ -510,7 +511,7 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 
 	/* check the DMA Status */
 	reg = dwc3_omap_readl(omap->base, USBOTGSS_SYSCONFIG);
-
+	irq_set_status_flags(omap->irq, IRQ_NOAUTOEN);
 	ret = devm_request_threaded_irq(dev, omap->irq, dwc3_omap_interrupt,
 					dwc3_omap_interrupt_thread, IRQF_SHARED,
 					"dwc3-omap", omap);

@@ -531,7 +532,7 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 	}
 
 	dwc3_omap_enable_irqs(omap);
-
+	enable_irq(omap->irq);
 	return 0;
 
 err2:

@@ -552,6 +553,7 @@ static int dwc3_omap_remove(struct platform_device *pdev)
 	extcon_unregister_notifier(omap->edev, EXTCON_USB, &omap->vbus_nb);
 	extcon_unregister_notifier(omap->edev, EXTCON_USB_HOST, &omap->id_nb);
 	dwc3_omap_disable_irqs(omap);
+	disable_irq(omap->irq);
 	of_platform_depopulate(omap->dev);
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

Signature · 1 line

2.10.1

Tony Lindgren

2016-12-12 21:10 UTC #1 lore raw

PATCH v2 1/1 usb: dwc3: omap: fix race of pm runtime with irq handler in probe

Quoted 25 lines · Grygorii Strashko

Now races can happen between interrupt handler execution and PM runtime in error handling code path in probe and in dwc3_omap_remove() which will lead to system crash:
in probe:
...
err1:
	pm_runtime_put_sync(dev);
^^ PM runtime can race with IRQ handler when deferred probing happening
   due to extcon
	pm_runtime_disable(dev);

	return ret;
in dwc3_omap_remove:
...
	dwc3_omap_disable_irqs(omap);
^^ IRQs are disabled in HW, but handler may still run
	of_platform_depopulate(omap->dev);
	pm_runtime_put_sync(&pdev->dev);
^^ PM runtime can race with IRQ handler
	pm_runtime_disable(&pdev->dev);

	return 0;

Quoted 2 lines

So, OMAP DWC3 IRQ need to be disabled before calling pm_runtime_put() in probe and in dwc3_omap_remove().

Acked-by Tony Lindgren <[email protected]>