From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793987869; b=eeAUlw5QhJWyEJvg5JMDqxZP1ngbFIlD+TLu3A0zyU6feJ5kFU/jR7/7Xa5QAJBlciTW xWSYO4JHYYQluU/PzrWrH8NrITru6QuJaguRjUzmM6ZD2j0gB6jAk/ntCDz64/Ct9flMv 9juuPJhS4dXvoSk8dfAMYC1iDo/w4ug3jHUKDhxlrzuF0mIKNDLkqPcyMkjfrM+AX1N91 qMpk7a3VNzM0QK2LfcKwY7aIXRKlattUaQLL1v+5xy1M2XTkrXzgxHO1GCVv7HGlcj04C agoTF5eeKISwS9qB19domdpU5m34dbflu2EiPklumLxS6+X9X6NogSGcRqhTlGitd0g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793987869; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=Inrsvx3wNYy2gwyot4kKfC79J4xMQXSJOaAwV6hp3/4=; b=E1qmbPJmY9RHzNcHD+LL2rLBD3QGJEz6mF8cgFNzIkQruNhizHlAu6shvyh0I/mL/22i AQB0hT0VibQHiMdx4cXsCNRa+kYIgniurWqppN2cjMudOhyG+HWRvzXfgnnpXSkW7jkEL GjMtCQ7kdEbZoVvWY6y9qmG66iIQLzxk/OB3DKMsksyeTjsqIHuk/MXQtnPi0B8MhAIo3 IbW3xKNJTJYjPR0qKFEGo6e88X88lQm/8f6hF2cfZa89UrOvc1oxo73t5X+2fSqTLjRWJ FqkxteEBiTz7Cz6x5Iuev2GUkjvGMGjFuOEG8IAC1EY9TqhP6+1pqlA0e89jBiXMezQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=YO0TvACn; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52C4D606A326 for ; Fri, 6 Nov 2026 17:57:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=YO0TvACn Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0A731F0089F; Fri, 6 Nov 2026 17:57:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793987868; bh=Inrsvx3wNYy2gwyot4kKfC79J4xMQXSJOaAwV6hp3/4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=YO0TvACn5D2cHhVUfZe8MK5rEsaeZZAsK8ENuJjKwpZgKYSokE34oxS/Z+stalIqU MbCa6ddVu0RWjJnbDx7iCPEegtI0lq0px+/NpZvS/sUTPcwjdwJkHHBnQeNZYFUvFv tv6cn8ycHcZFGe8MCHYdc0YyxNcdtfocydFCkkY2HN50CNyyO6B3xTS+2qLQrYtKrH mPiV8QibnqtbILrN507xWwAuDAQCZ4js/86J1t+8UVMJ1q0Sxl8P1XM3S818NeRO+5 LDc9V2borOJnMXX0zVfFhterONRnkaI3hiOAwkWZCUUGc02Pdb6gK5SkLwawqp2sJs det7OGi09gDDw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 2/6] usb: dwc2: fix a possible interrupt storm in hcd resume Reply-To: sashiko-reviews@lists.linux.dev To: "Fabrice Gasnier" Cc: linux-usb@vger.kernel.org In-Reply-To: <20261106-dwc2-low-power-fixes-stm32-v3-2-68d2a0e9bab6@foss.st.com> References: <20261106-dwc2-low-power-fixes-stm32-v3-0-68d2a0e9bab6@foss.st.com> <20261106-dwc2-low-power-fixes-stm32-v3-2-68d2a0e9bab6@foss.st.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 06 Nov 2026 17:57:48 +0000 X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [Medium] usb: dwc2: unlocked dwc2_hcd_reinit() call in _dwc2_hcd_resume() -- commit 57723fb6e396e93ffaf40174f532484ee2100bb5 Author: Fabrice Gasnier usb: dwc2: fix a possible interrupt storm in hcd resume This commit moves set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags) before dwc2_hcd_reinit() in _dwc2_hcd_resume() so that host interrupts enabled during reinitialization are not rejected as unhandled. > diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c > index d5275cd658d4c..28cde15e0cca4 100644 > --- a/drivers/usb/dwc2/hcd.c > +++ b/drivers/usb/dwc2/hcd.c > @@ -4469,14 +4469,14 @@ static int _dwc2_hcd_resume(struct usb_hcd *hcd) > */ > dwc2_core_init(hsotg, false); > dwc2_enable_global_interrupts(hsotg); > - dwc2_hcd_reinit(hsotg); > - spin_lock_irqsave(&hsotg->lock, flags); > =20 > /* > * Set HW accessible bit before powering on the controller > * since an interrupt may rise. > */ > set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags); > + dwc2_hcd_reinit(hsotg); > + spin_lock_irqsave(&hsotg->lock, flags); > break; [Severity: Medium] Should spin_lock_irqsave(&hsotg->lock, flags) be acquired before setting HCD_FLAG_HW_ACCESSIBLE and calling dwc2_hcd_reinit(hsotg)? dwc2_hcd_reinit() requires interrupts disabled and hsotg->lock held, as its only other caller _dwc2_hcd_start() does: drivers/usb/dwc2/hcd.c:dwc2_hcd_reinit() { /* * Initializes dynamic portions of the DWC_otg HCD state * * Must be called with interrupt disabled and spinlock held */ static void dwc2_hcd_reinit(struct dwc2_hsotg *hsotg) } With HCD_FLAG_HW_ACCESSIBLE now set before dwc2_hcd_reinit(hsotg) while interrupts are enabled and hsotg->lock is unlocked, a host interrupt can enter usb_hcd_irq() -> _dwc2_hcd_irq() -> dwc2_handle_hcd_intr() (or a concurrent caller can take hsotg->lock) while dwc2_hcd_reinit() is modifying hsotg->flags.d32, hsotg->free_hc_list, channel states, and host registers: _dwc2_hcd_resume() dwc2_enable_global_interrupts(hsotg) set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags) dwc2_hcd_reinit(hsotg) list_del_init(&chan->hc_list_entry) usb_hcd_irq() _dwc2_hcd_irq() dwc2_handle_hcd_intr() <-- races on hsotg state and lists spin_lock_irqsave(&hsotg->lock, flags) Neither set_bit() nor dwc2_hcd_reinit() sleeps, so acquiring hsotg->lock before enabling global interrupts, setting HCD_FLAG_HW_ACCESSIBLE, and calling dwc2_hcd_reinit() would avoid this race. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261106-dwc2-low-p= ower-fixes-stm32-v3-0-68d2a0e9bab6@foss.st.com?part=3D2