From: Douglas Anderson Date: Fri, 20 Nov 2015 17:06:27 +0000 (-0800) Subject: usb: dwc2: host: Add missing spinlock in dwc2_hcd_reset_func() X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=4a065c7bdbec9536f7b899241b125b9c3b5ba97a;p=deliverable%2Flinux.git usb: dwc2: host: Add missing spinlock in dwc2_hcd_reset_func() 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 Signed-off-by: Felipe Balbi --- diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index cbfdcb804adb..880b549f737a 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -2358,13 +2358,19 @@ 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); } /*