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 83E05C001E0 for ; Mon, 24 Jul 2023 01:37:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231853AbjGXBhQ (ORCPT ); Sun, 23 Jul 2023 21:37:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231791AbjGXBgi (ORCPT ); Sun, 23 Jul 2023 21:36:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D65B59F6; Sun, 23 Jul 2023 18:33:02 -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 B289A60F25; Mon, 24 Jul 2023 01:31:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7336AC433C8; Mon, 24 Jul 2023 01:31:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690162309; bh=M6LrzzuU4c4hEekCPHry8e/a9qHh0p6vF4b+LERkyLs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b4NNBqTXa+0MpfvkKkQ8WvbBjOS+32x5ot1fB7zXe/vkQFLVRCZMc6acEO4UP0LEV HzSmCxbsxGFqWoVeFTCjxKwcZAW6GLSGX31KWXYTDA23BBlZ94WK100vUCXf3ptdxk VLI42Q+BMBevqSBbPjzdFI0n67FntosICmMNqYSaD6cd9dMAmX0TpgoPZFoC9qjC2G IMiy7Ug/nmKBXu02jvHS/ZdjRYsUiItpetFpRqAE03wByq+XuHL47ZFfsMj+u6WNkO /Q7A9OV53CqDBJ0+whCLSaFVbMDrCebzX/BRf8oHd+JvXvCILWpeQJFtGsLuOi6xIG OVcyJyu1eaCHg== 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 6.4 05/40] usb: gadget: u_serial: Avoid spinlock recursion in __gs_console_push Date: Sun, 23 Jul 2023 21:31:05 -0400 Message-Id: <20230724013140.2327815-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230724013140.2327815-1-sashal@kernel.org> References: <20230724013140.2327815-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.4.5 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 a0ca47fbff0fc..1bc96ff954ffe 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -916,8 +916,11 @@ 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