From nobody Sat May 9 11:04:58 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F953C433F5 for ; Wed, 18 May 2022 06:13:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230464AbiERGN2 (ORCPT ); Wed, 18 May 2022 02:13:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230403AbiERGNZ (ORCPT ); Wed, 18 May 2022 02:13:25 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B66454DF67 for ; Tue, 17 May 2022 23:13:21 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-2fef1441caaso12073477b3.6 for ; Tue, 17 May 2022 23:13:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=qdumKa4FBuTxuZUv3F0lK1XSfSq71XoSNJznwmGquGM=; b=UZ0XzqGFyIRUXC3XR4/VnzNa5pkMteEGw9q++34hDNEuUG45TA4QDABcKn6K4+mDBY l7Ivyf2LlRsOnsDezdIQaNiupPyubwcYfFSz78nu+TEnezztwdD0p9OULhbGa/kQ4dhQ LhoW/Zt6nA4qmQrdJL3izOx01eMr3gUdJg7645B3+3tV70bBPw9iy1SuGE9e5FBfdO26 rnKeMl0L5rKz4hQw3f0/wJP3L9NWNu093LUZzo+Y/pBR38bydJHtnNmGp4JIcVr2M6Sn 4NQ+SSeA32kwYy2Sbi05N/WKP8ccmHpZvwDmDW53gW756hlyOHHE59E8Khz4fgl/r3mv DAgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=qdumKa4FBuTxuZUv3F0lK1XSfSq71XoSNJznwmGquGM=; b=q/hRUdxLfjn/jFZS5vTDqJDT2pfU8rUblU0W+Eq57vI40ZlDXnirIPlzTFB+vWsXVW 8soK1zRqUYu4Fn/UgsaPTMsvMfT27MkAhoBH/1ODJq3bcQ9OxLYmkScANOd/slbMaj6E jI+rqdlM9vNE3EBiDlr+d9vwpYJqYiVEmnXof07/Tk3yhNWMJNBXLhLe1unh/RkXkQtW dDwFhFaj1cHPSYnZZ4GpqoXTmJh5K+glX6QoZkN4o971dysmavvSK5jnT7xjevENU83j CRb5Gkbo2qeikivcV+L3ddjfy+FA3A9aSv3Bz7mllXPh3waBX7zF8i+/pto7ljn0HmU/ 9YIA== X-Gm-Message-State: AOAM5331OL02x2D8myu11NzjIGJuU/v4SrTcrRwm/XEdMdcevrKz1xu9 oJpGhhc8HV1y47hmR0IUe7PsGPJRvf7vPLVGlKA= X-Google-Smtp-Source: ABdhPJwNXQdoayoEo7D/1Qer+YG/oJ4ICu4ESGhezth/PoFtz4/B+AmIFIfwCrkCSr84e0m/YmL6j0k4SAthbBy+nZI= X-Received: from albertccwang.ntc.corp.google.com ([2401:fa00:fc:202:3413:e42f:31c4:c4e8]) (user=albertccwang job=sendgmr) by 2002:a25:264e:0:b0:64d:e13f:7911 with SMTP id m75-20020a25264e000000b0064de13f7911mr9913828ybm.27.1652854400861; Tue, 17 May 2022 23:13:20 -0700 (PDT) Date: Wed, 18 May 2022 14:13:15 +0800 Message-Id: <20220518061315.3359198-1-albertccwang@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.36.1.124.g0e6072fb45-goog Subject: [PATCH v5] usb: dwc3: gadget: Move null pinter check to proper place From: Albert Wang To: balbi@kernel.org, gregkh@linuxfoundation.org, quic_jackp@quicinc.com Cc: badhri@google.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Albert Wang Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When dwc3_gadget_ep_cleanup_completed_requests() called to dwc3_gadget_giveback() where the dwc3 lock is released, other thread is able to execute. In this situation, usb_ep_disable() gets the chance to clear endpoint descriptor pointer which leds to the null pointer dereference problem. So needs to move the null pointer check to a proper place. Example call stack: Thread#1: dwc3_thread_interrupt() spin_lock -> dwc3_process_event_buf() -> dwc3_process_event_entry() -> dwc3_endpoint_interrupt() -> dwc3_gadget_endpoint_trbs_complete() -> dwc3_gadget_ep_cleanup_completed_requests() ... -> dwc3_giveback() spin_unlock Thread#2 executes Thread#2: configfs_composite_disconnect() -> __composite_disconnect() -> ffs_func_disable() -> ffs_func_set_alt() -> ffs_func_eps_disable() -> usb_ep_disable() wait for dwc3 spin_lock Thread#1 released lock clear endpoint.desc Fixes: 26288448120b ("usb: dwc3: gadget: Fix null pointer exception") Signed-off-by: Albert Wang --- v5: Supplement the change log v4: Modify the change log text v3: Add change log to be compliant with the canonical patch format v2: Remove redundant 'else' and add additional comments and more descriptive commit text drivers/usb/dwc3/gadget.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 19477f4bbf54..7edd4a5dc6af 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -3366,14 +3366,14 @@ static bool dwc3_gadget_endpoint_trbs_complete(stru= ct dwc3_ep *dep, struct dwc3 *dwc =3D dep->dwc; bool no_started_trb =3D true; =20 - if (!dep->endpoint.desc) - return no_started_trb; - dwc3_gadget_ep_cleanup_completed_requests(dep, event, status); =20 if (dep->flags & DWC3_EP_END_TRANSFER_PENDING) goto out; =20 + if (!dep->endpoint.desc) + return no_started_trb; + if (usb_endpoint_xfer_isoc(dep->endpoint.desc) && list_empty(&dep->started_list) && (list_empty(&dep->pending_list) || status =3D=3D -EXDEV)) --=20 2.36.1.124.g0e6072fb45-goog