From patchwork Mon Feb 28 17:24:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 547219 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 CD8E7C433FE for ; Mon, 28 Feb 2022 17:28:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235697AbiB1R3B (ORCPT ); Mon, 28 Feb 2022 12:29:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235175AbiB1R2w (ORCPT ); Mon, 28 Feb 2022 12:28:52 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9442541AB; Mon, 28 Feb 2022 09:27:50 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 20F166140B; Mon, 28 Feb 2022 17:27:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A0A0C340F6; Mon, 28 Feb 2022 17:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646069269; bh=DPO3BcLiwBn8PmDoRW5r8RbBNLCnhtbo3AwL7su6q/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c7FT4qGKiXhOYI9GAVAt+FHrHIB0eZlckaOG8yVgKwJx88lHgk221tif+RfLEvKvD vGMDYeciloZz5oONBrhvu+S01xM/kgFQ6+HflfOF3Ss64cXh2tlRQ9T6j1xY7BtowN moPl+xvLNKmgDRHNwXFPrx/Z7L5xz2HYnp5rxOms= 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 4.14 24/31] usb: dwc3: gadget: Let the interrupt handler disable bottom halves. Date: Mon, 28 Feb 2022 18:24:20 +0100 Message-Id: <20220228172202.213218587@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220228172159.515152296@linuxfoundation.org> References: <20220228172159.515152296@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 @@ -3153,9 +3153,11 @@ 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; }