From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+sZ/yVTo4HZsvpVQ4lvQYoX9gYLlpz6vvR2UU0aI+cu0fiSisSq5HpT33F9olKKHtRr3ZD ARC-Seal: i=1; a=rsa-sha256; t=1524405424; cv=none; d=google.com; s=arc-20160816; b=VzT9SmbSVonTe07ZaR94OWl2LPGwGmGqr2FJ11oNZXTH7B772K8juQqBsvwrxGIESE pWZmxFxwm7UFcgbU7yRFQBz5vXwHKfYLLyH6Yg7DIEaWs520TQ6xJgxkRyfavVnJf/7e hZlgam9Vm7jDzQEPsoNv3gA0tACzNUFFdfECrbAUd29UJYEyhH+onscH5TLw/P9Dqbst BKXVS8JHm/jPnaQE8IdA7/ZBURg4JseuoWR8vaU0SWWDfG+7jfbIB4kVxk6m0TelVMrC xsW1RFQ+tcRx9HgK5vLnKPGQaN5Nldx96M8m2qr6ibMSXrGn37Z+zCcpXQ2ftIEFp/SV P42w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=8/GZbm7aH3ZYkgC3ocCdNkmDiH7XVh6P4ZvrDHXr75Q=; b=UCzgp6cU6ojuhnAXsZ+8gV+6JWBawtDNVtptmInBeF5kT0j+3TTDNK4943PerL3Dbz 5lWNvEjDqtzTdKK7qjGxXwZbQoFUiFguS1CpcTCabfl0GsI3bLHYv5b087V7FtlHbpuK CK9fZaMqhm7ySckZ5zSZea4sv/BU25ZMQFsWWohTdXJxqM2usqcWPewxlQeyJlsULnba hTahAbjHYeRC5gLNW56MLbPO3p8aaJLP9fkLhGDXWcjWgirLr0kCUyrIPp+ts6V/cfkc fOTrgFLzgymka7nVctZtdd9GvT4SwCHJImMHkx+ecDX6JU5HXdo/5pUYOef3bNLyyCOW ZCoA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tuba Yavuz , Felipe Balbi Subject: [PATCH 4.16 044/196] usb: dwc3: gadget: never call ->complete() from ->ep_queue() Date: Sun, 22 Apr 2018 15:51:04 +0200 Message-Id: <20180422135106.353321075@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135104.278511750@linuxfoundation.org> References: <20180422135104.278511750@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598454942163672502?= X-GMAIL-MSGID: =?utf-8?q?1598454942163672502?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Felipe Balbi commit c91815b596245fd7da349ecc43c8def670d2269e upstream. This is a requirement which has always existed but, somehow, wasn't reflected in the documentation and problems weren't found until now when Tuba Yavuz found a possible deadlock happening between dwc3 and f_hid. She described the situation as follows: spin_lock_irqsave(&hidg->write_spinlock, flags); // first acquire /* we our function has been disabled by host */ if (!hidg->req) { free_ep_req(hidg->in_ep, hidg->req); goto try_again; } [...] status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC); => [...] => usb_gadget_giveback_request => f_hidg_req_complete => spin_lock_irqsave(&hidg->write_spinlock, flags); // second acquire Note that this happens because dwc3 would call ->complete() on a failed usb_ep_queue() due to failed Start Transfer command. This is, anyway, a theoretical situation because dwc3 currently uses "No Response Update Transfer" command for Bulk and Interrupt endpoints. It's still good to make this case impossible to happen even if the "No Reponse Update Transfer" command is changed. Reported-by: Tuba Yavuz Signed-off-by: Felipe Balbi Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/gadget.c | 43 +++++++++++++++++++++++++------------------ 1 file changed, 25 insertions(+), 18 deletions(-) --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -166,18 +166,8 @@ static void dwc3_ep_inc_deq(struct dwc3_ dwc3_ep_inc_trb(&dep->trb_dequeue); } -/** - * dwc3_gadget_giveback - call struct usb_request's ->complete callback - * @dep: The endpoint to whom the request belongs to - * @req: The request we're giving back - * @status: completion code for the request - * - * Must be called with controller's lock held and interrupts disabled. This - * function will unmap @req and call its ->complete() callback to notify upper - * layers that it has completed. - */ -void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req, - int status) +void dwc3_gadget_del_and_unmap_request(struct dwc3_ep *dep, + struct dwc3_request *req, int status) { struct dwc3 *dwc = dep->dwc; @@ -190,18 +180,35 @@ void dwc3_gadget_giveback(struct dwc3_ep if (req->trb) usb_gadget_unmap_request_by_dev(dwc->sysdev, - &req->request, req->direction); + &req->request, req->direction); req->trb = NULL; - trace_dwc3_gadget_giveback(req); + if (dep->number > 1) + pm_runtime_put(dwc->dev); +} + +/** + * dwc3_gadget_giveback - call struct usb_request's ->complete callback + * @dep: The endpoint to whom the request belongs to + * @req: The request we're giving back + * @status: completion code for the request + * + * Must be called with controller's lock held and interrupts disabled. This + * function will unmap @req and call its ->complete() callback to notify upper + * layers that it has completed. + */ +void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req, + int status) +{ + struct dwc3 *dwc = dep->dwc; + + dwc3_gadget_del_and_unmap_request(dep, req, status); + spin_unlock(&dwc->lock); usb_gadget_giveback_request(&dep->endpoint, &req->request); spin_lock(&dwc->lock); - - if (dep->number > 1) - pm_runtime_put(dwc->dev); } /** @@ -1227,7 +1234,7 @@ static int __dwc3_gadget_kick_transfer(s if (req->trb) memset(req->trb, 0, sizeof(struct dwc3_trb)); dep->queued_requests--; - dwc3_gadget_giveback(dep, req, ret); + dwc3_gadget_del_and_unmap_request(dep, req, ret); return ret; }