[PATCH for v4.9 LTS 27/87] usb: dwc3: omap: fix race of pm runtime with irq handler in probe

From: Levin, Alexander (Sasha Levin)
Date: Fri Jul 14 2017 - 21:27:14 EST


From: Grygorii Strashko <grygorii.strashko@xxxxxx>

[ Upstream commit 12a7f17fac5b370bec87259e4c718faf563ce900 ]

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().

Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
drivers/usb/dwc3/dwc3-omap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
index 5dd1832564c7..35b63518baf6 100644
--- a/drivers/usb/dwc3/dwc3-omap.c
+++ b/drivers/usb/dwc3/dwc3-omap.c
@@ -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>
@@ -511,7 +512,7 @@ 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);
@@ -532,7 +533,7 @@ static int dwc3_omap_probe(struct platform_device *pdev)
}

dwc3_omap_enable_irqs(omap);
-
+ enable_irq(omap->irq);
return 0;

err2:
@@ -553,6 +554,7 @@ 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);
--
2.11.0