From patchwork Mon Feb 28 17:24:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 546976 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 CE965C4321E for ; Mon, 28 Feb 2022 18:11:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239931AbiB1SLx (ORCPT ); Mon, 28 Feb 2022 13:11:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240498AbiB1SJA (ORCPT ); Mon, 28 Feb 2022 13:09:00 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B31CD5DE5E; Mon, 28 Feb 2022 09:48:36 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 0EFEFCE1795; Mon, 28 Feb 2022 17:48:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBBC2C340E7; Mon, 28 Feb 2022 17:48:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646070505; bh=bHavJjo8Tb1+1QO5Z8TYuLDXUUuT+DNd/J37Wc1hUSk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sZHgJ9j/uFG8vXSeJ5ZmDPvPbQTRyxGQtjs5itAGaIP98Vh76fgFgJiIl5wEOZb8Y OpvUhIb/1br2uKemvuWgLRUlshJO8dsPPpxXIZ3DxFLDEOUIJaG7s8QE/VMyVP2Oxp sR3uAz4UrpwBLfdBRiLXCNWUQ8yKWekZuzSrLKWI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, stable , Marek Szyprowski , Sebastian Andrzej Siewior Subject: [PATCH 5.16 132/164] usb: dwc3: gadget: Let the interrupt handler disable bottom halves. Date: Mon, 28 Feb 2022 18:24:54 +0100 Message-Id: <20220228172412.033096286@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220228172359.567256961@linuxfoundation.org> References: <20220228172359.567256961@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sebastian Andrzej Siewior commit 84918a89d6efaff075de570b55642b6f4ceeac6d upstream. The interrupt service routine registered for the gadget is a primary handler which mask the interrupt source and a threaded handler which handles the source of the interrupt. Since the threaded handler is voluntary threaded, the IRQ-core does not disable bottom halves before invoke the handler like it does for the forced-threaded handler. Due to changes in networking it became visible that a network gadget's completions handler may schedule a softirq which remains unprocessed. The gadget's completion handler is usually invoked either in hard-IRQ or soft-IRQ context. In this context it is enough to just raise the softirq because the softirq itself will be handled once that context is left. In the case of the voluntary threaded handler, there is nothing that will process pending softirqs. Which means it remain queued until another random interrupt (on this CPU) fires and handles it on its exit path or another thread locks and unlocks a lock with the bh suffix. Worst case is that the CPU goes idle and the NOHZ complains about unhandled softirqs. Disable bottom halves before acquiring the lock (and disabling interrupts) and enable them after dropping the lock. This ensures that any pending softirqs will handled right away. Link: https://lkml.kernel.org/r/c2a64979-73d1-2c22-e048-c275c9f81558@samsung.com Fixes: e5f68b4a3e7b0 ("Revert "usb: dwc3: gadget: remove unnecessary _irqsave()"") Cc: stable Reported-by: Marek Szyprowski Tested-by: Marek Szyprowski Signed-off-by: Sebastian Andrzej Siewior Link: https://lore.kernel.org/r/Yg/YPejVQH3KkRVd@linutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/gadget.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4131,9 +4131,11 @@ static irqreturn_t dwc3_thread_interrupt unsigned long flags; irqreturn_t ret = IRQ_NONE; + local_bh_disable(); spin_lock_irqsave(&dwc->lock, flags); ret = dwc3_process_event_buf(evt); spin_unlock_irqrestore(&dwc->lock, flags); + local_bh_enable(); return ret; }