The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
62c73bfea048 ("usb: dwc3: Fix race between dwc3_set_mode and __dwc3_set_mode") 07903626d988 ("usb: dwc3: core: Do not perform GCTL_CORE_SOFTRESET during bootup") afbd04e66e5d ("usb: dwc3: core: Deprecate GCTL.CORESOFTRESET") f88359e1588b ("usb: dwc3: core: Do core softreset when switch mode") f580170f135a ("usb: dwc3: Add splitdisable quirk for Hisilicon Kirin Soc") dc336b19e82d ("usb: dwc3: core: do not queue work if dr_mode is not USB_DR_MODE_OTG") c2cd3452d5f8 ("usb: dwc3: support continuous runtime PM with dual role")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 62c73bfea048e66168df09da6d3e4510ecda40bb Mon Sep 17 00:00:00 2001 From: Sven Peter sven@svenpeter.dev Date: Mon, 28 Nov 2022 17:15:26 +0100 Subject: [PATCH] usb: dwc3: Fix race between dwc3_set_mode and __dwc3_set_mode
dwc->desired_dr_role is changed by dwc3_set_mode inside a spinlock but then read by __dwc3_set_mode outside of that lock. This can lead to a race condition when very quick successive role switch events happen:
CPU A dwc3_set_mode(DWC3_GCTL_PRTCAP_HOST) // first role switch event spin_lock_irqsave(&dwc->lock, flags); dwc->desired_dr_role = mode; // DWC3_GCTL_PRTCAP_HOST spin_unlock_irqrestore(&dwc->lock, flags); queue_work(system_freezable_wq, &dwc->drd_work);
CPU B __dwc3_set_mode // .... spin_lock_irqsave(&dwc->lock, flags); // desired_dr_role is DWC3_GCTL_PRTCAP_HOST dwc3_set_prtcap(dwc, dwc->desired_dr_role); spin_unlock_irqrestore(&dwc->lock, flags);
CPU A dwc3_set_mode(DWC3_GCTL_PRTCAP_DEVICE) // second event spin_lock_irqsave(&dwc->lock, flags); dwc->desired_dr_role = mode; // DWC3_GCTL_PRTCAP_DEVICE spin_unlock_irqrestore(&dwc->lock, flags);
CPU B (continues running __dwc3_set_mode) switch (dwc->desired_dr_role) { // DWC3_GCTL_PRTCAP_DEVICE // .... case DWC3_GCTL_PRTCAP_DEVICE: // .... ret = dwc3_gadget_init(dwc);
We then have DWC3_GCTL.DWC3_GCTL_PRTCAPDIR = DWC3_GCTL_PRTCAP_HOST and dwc->current_dr_role = DWC3_GCTL_PRTCAP_HOST but initialized the controller in device mode. It's also possible to get into a state where both host and device are intialized at the same time. Fix this race by creating a local copy of desired_dr_role inside __dwc3_set_mode while holding dwc->lock.
Fixes: 41ce1456e1db ("usb: dwc3: core: make dwc3_set_mode() work properly") Cc: stable stable@kernel.org Acked-by: Thinh Nguyen Thinh.Nguyen@synopsys.com Signed-off-by: Sven Peter sven@svenpeter.dev Link: https://lore.kernel.org/r/20221128161526.79730-1-sven@svenpeter.dev Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 1f348bc867c2..fc38a8b13efa 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -122,21 +122,25 @@ static void __dwc3_set_mode(struct work_struct *work) unsigned long flags; int ret; u32 reg; + u32 desired_dr_role;
mutex_lock(&dwc->mutex); + spin_lock_irqsave(&dwc->lock, flags); + desired_dr_role = dwc->desired_dr_role; + spin_unlock_irqrestore(&dwc->lock, flags);
pm_runtime_get_sync(dwc->dev);
if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_OTG) dwc3_otg_update(dwc, 0);
- if (!dwc->desired_dr_role) + if (!desired_dr_role) goto out;
- if (dwc->desired_dr_role == dwc->current_dr_role) + if (desired_dr_role == dwc->current_dr_role) goto out;
- if (dwc->desired_dr_role == DWC3_GCTL_PRTCAP_OTG && dwc->edev) + if (desired_dr_role == DWC3_GCTL_PRTCAP_OTG && dwc->edev) goto out;
switch (dwc->current_dr_role) { @@ -164,7 +168,7 @@ static void __dwc3_set_mode(struct work_struct *work) */ if (dwc->current_dr_role && ((DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC31, 190A)) && - dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG)) { + desired_dr_role != DWC3_GCTL_PRTCAP_OTG)) { reg = dwc3_readl(dwc->regs, DWC3_GCTL); reg |= DWC3_GCTL_CORESOFTRESET; dwc3_writel(dwc->regs, DWC3_GCTL, reg); @@ -184,11 +188,11 @@ static void __dwc3_set_mode(struct work_struct *work)
spin_lock_irqsave(&dwc->lock, flags);
- dwc3_set_prtcap(dwc, dwc->desired_dr_role); + dwc3_set_prtcap(dwc, desired_dr_role);
spin_unlock_irqrestore(&dwc->lock, flags);
- switch (dwc->desired_dr_role) { + switch (desired_dr_role) { case DWC3_GCTL_PRTCAP_HOST: ret = dwc3_host_init(dwc); if (ret) {