From mboxrd@z Thu Jan 1 00:00:00 1970 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 4B406C001B0 for ; Mon, 24 Jul 2023 01:40:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231418AbjGXBks (ORCPT ); Sun, 23 Jul 2023 21:40:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232058AbjGXBkH (ORCPT ); Sun, 23 Jul 2023 21:40:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4B364682; Sun, 23 Jul 2023 18:35:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F007260FD0; Mon, 24 Jul 2023 01:32:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A77B4C433CA; Mon, 24 Jul 2023 01:32:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690162366; bh=GLv9J9Q1GULk2tk6a21BWz9R/YTSf1sjlRUmrDHNGhE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rd2TDaFgAUUvQ8vfDcU6n4akQcaBGUt9sTf3qB705qQ7VtUOOheMWcl4xtzoKSWnN jDAa2A6fRCoxSmNPMQdUupmDvMiljCMob0TQimrirDPbUGwB2A5sFmT1Yd9WwXOzG8 VqBBQiOYYGtLLdIAvemcaiPzZAsXjpmsGZ6HRTDyIj0LhFrN6eTJ5+66TH41OUtHpS BVBx1cyBT1PXkrCMiJyU0HHQAawl8i3RikQn/bw6LJPb+vfJwSeEVt1CGR1xIDJ1/Q trNCJTmnqDCJ0Xq8LQQZh1zKI+cvt6Hion15bTPwyU21Ha854thGjQAKw26T/hT7nK 22icnmRybIAzA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Prashanth K , Greg Kroah-Hartman , Sasha Levin , balbi@kernel.org, linux-usb@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 05/34] usb: gadget: u_serial: Avoid spinlock recursion in __gs_console_push Date: Sun, 23 Jul 2023 21:32:08 -0400 Message-Id: <20230724013238.2329166-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230724013238.2329166-1-sashal@kernel.org> References: <20230724013238.2329166-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.40 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Prashanth K [ Upstream commit e5990469943c711cb00bfde6338d2add6c6d0bfe ] When serial console over USB is enabled, gs_console_connect queues gs_console_work, where it acquires the spinlock and queues the usb request, and this request goes to gadget layer. Now consider a situation where gadget layer prints something to dmesg, this will eventually call gs_console_write() which requires cons->lock. And this causes spinlock recursion. Avoid this by excluding usb_ep_queue from the spinlock. spin_lock_irqsave //needs cons->lock gs_console_write . . _printk __warn_printk dev_warn/pr_err . . [USB Gadget Layer] . . usb_ep_queue gs_console_work __gs_console_push // acquires cons->lock process_one_work Signed-off-by: Prashanth K Link: https://lore.kernel.org/r/1683638872-6885-1-git-send-email-quic_prashk@quicinc.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/u_serial.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index db6fd0238d4b4..2dcd30c96e20d 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -915,8 +915,11 @@ static void __gs_console_push(struct gs_console *cons) } req->length = size; + + spin_unlock_irq(&cons->lock); if (usb_ep_queue(ep, req, GFP_ATOMIC)) req->length = 0; + spin_lock_irq(&cons->lock); } static void gs_console_work(struct work_struct *work) -- 2.39.2