On 11/20/2015 9:06 AM, Douglas Anderson wrote:
> The dwc2_hcd_reset_func() function is only ever called directly by a
> delayed work function. As such no locks are already held when the
> function is called.
>
> Doing a read-modify-write of CPU registers and setting fields in the
> main hsotg data structure is a bad idea without locks. Let's add
> locks.
>
> The bug was found by code inspection only. It turns out that the
> dwc2_hcd_reset_func() is only ever called today if the
> "host_support_fs_ls_low_power" parameter is enabled and no code in
> mainline enables that parameter. Thus no known issues in mainline are
> fixed by this patch, but it's still probably wise to fix the function.
>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
> Changes in v5:
> - New for v5 of the series
>
> drivers/usb/dwc2/hcd.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index 42b6c5127618..e8924cecc83a 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -2357,13 +2357,19 @@ static void dwc2_hcd_reset_func(struct work_struct *work)
> {
> struct dwc2_hsotg *hsotg = container_of(work, struct dwc2_hsotg,
> reset_work.work);
> + unsigned long flags;
> u32 hprt0;
>
> dev_dbg(hsotg->dev, "USB RESET function called\n");
> +
> + spin_lock_irqsave(&hsotg->lock, flags);
> +
> hprt0 = dwc2_read_hprt0(hsotg);
> hprt0 &= ~HPRT0_RST;
> dwc2_writel(hprt0, hsotg->regs + HPRT0);
> hsotg->flags.b.port_reset_change = 1;
> +
> + spin_unlock_irqrestore(&hsotg->lock, flags);
> }
>
> /*
>
Acked-by: John Youn <johnyoun@xxxxxxxxxxxx>
John
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