| Message ID | 20221128063207.100596-1-duoming@zju.edu.cn |
|---|---|
| State | New |
| Headers | show |
| Series | usb: mtu3: fix sleep-in-atomic-context bug caused by usleep_range() | expand |
On Mon, Nov 28, 2022 at 02:32:07PM +0800, Duoming Zhou wrote: > The function zero_autoresume() is a timer handler that runs in > atomic context. It is used to wake up the host connected to the > gadget. when used by usb mtu3, the zero_autoresume() calls > usleep_range() that can sleep. As a result, the sleep-in-atomic- > context bug will happen. The process is shown below. > > (atomic context) > zero_autoresume() > usb_gadget_wakeup() > mtu3_gadget_wakeup() > usleep_range() //sleep > > This patch changes usleep_range(10000, 11000) to mdelay(10) > in order to mitigate the bug. > > Fixes: df2069acb005 ("usb: Add MediaTek USB3 DRD driver") > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > --- > drivers/usb/mtu3/mtu3_gadget.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/mtu3/mtu3_gadget.c b/drivers/usb/mtu3/mtu3_gadget.c > index 80236e7b089..e366c4a97d7 100644 > --- a/drivers/usb/mtu3/mtu3_gadget.c > +++ b/drivers/usb/mtu3/mtu3_gadget.c > @@ -468,7 +468,7 @@ static int mtu3_gadget_wakeup(struct usb_gadget *gadget) > } else { > mtu3_setbits(mtu->mac_base, U3D_POWER_MANAGEMENT, RESUME); > spin_unlock_irqrestore(&mtu->lock, flags); > - usleep_range(10000, 11000); > + mdelay(10); > spin_lock_irqsave(&mtu->lock, flags); > mtu3_clrbits(mtu->mac_base, U3D_POWER_MANAGEMENT, RESUME); > } > -- > 2.17.1 > Have you tested this on real hardware? How come the original code does not trigger any run-time warnings? Does your change solve the runtime issue? thanks, greg k-h
diff --git a/drivers/usb/mtu3/mtu3_gadget.c b/drivers/usb/mtu3/mtu3_gadget.c index 80236e7b089..e366c4a97d7 100644 --- a/drivers/usb/mtu3/mtu3_gadget.c +++ b/drivers/usb/mtu3/mtu3_gadget.c @@ -468,7 +468,7 @@ static int mtu3_gadget_wakeup(struct usb_gadget *gadget) } else { mtu3_setbits(mtu->mac_base, U3D_POWER_MANAGEMENT, RESUME); spin_unlock_irqrestore(&mtu->lock, flags); - usleep_range(10000, 11000); + mdelay(10); spin_lock_irqsave(&mtu->lock, flags); mtu3_clrbits(mtu->mac_base, U3D_POWER_MANAGEMENT, RESUME); }
The function zero_autoresume() is a timer handler that runs in atomic context. It is used to wake up the host connected to the gadget. when used by usb mtu3, the zero_autoresume() calls usleep_range() that can sleep. As a result, the sleep-in-atomic- context bug will happen. The process is shown below. (atomic context) zero_autoresume() usb_gadget_wakeup() mtu3_gadget_wakeup() usleep_range() //sleep This patch changes usleep_range(10000, 11000) to mdelay(10) in order to mitigate the bug. Fixes: df2069acb005 ("usb: Add MediaTek USB3 DRD driver") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- drivers/usb/mtu3/mtu3_gadget.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)