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 X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 494BFC432C3 for ; Sun, 24 Nov 2019 23:00:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F3EA207FD for ; Sun, 24 Nov 2019 23:00:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lEnE6f+4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727029AbfKXXAd (ORCPT ); Sun, 24 Nov 2019 18:00:33 -0500 Received: from mail-il1-f193.google.com ([209.85.166.193]:35307 "EHLO mail-il1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726855AbfKXXAd (ORCPT ); Sun, 24 Nov 2019 18:00:33 -0500 Received: by mail-il1-f193.google.com with SMTP id g12so3011559ild.2; Sun, 24 Nov 2019 15:00:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=odza52ilBwlA3qR/sWBKfuk+gEqR3R+QpYiXACzCFos=; b=lEnE6f+4W6HZwageKml38lXSUMQYQ2zwYrERviQkywOciokwQJlcVArXQlhb5DNI4T hAu+vPMlYTsH/QUWiOtkNPaFE43mo0DdOLwZQJinp1qP007Q1pYUN2YBUuWt68JLHnyw QhjqYawiKtrk5pFnpodSFBhlHA1AraKCTw34bJnzIlblBlNTv4/59OcR26uXVSGnjbqu 8CMB79FUGM4F07WVpg0vuECMFzvaOLgmF4MTmNWvW5qfYi/K2vzduafn/JNvjmTFq34Y hUYaQjHCNAeOXyLnd886cq9Y7e/gh0knc8cpAUvTI2e5O0lEfter1xwvnZVV1VBmSrI8 Rh5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=odza52ilBwlA3qR/sWBKfuk+gEqR3R+QpYiXACzCFos=; b=tH6iiZLNYIEyWPN4spluiKyvo1ujzEoHj04CVysUYeAYUQ8iQrem7lmWX2gUmQf0KK BQBhci+YbFaj+0rMST9SXWcwIOAn5GuId2t7QKui5SqbwW+FPpUeloja3r91SF8UZsRf L6aTX9pvUO1NCLOp/FMfXQSORMR7VQdUPYmBspZYSvHGMevB8rNdrmpmW7Slfjc4b7CN Ct3seN9mboCeZbBF17i5JJyojhEBrZP3cs3gNCZcxlcFr0S+T4gCcYxnJ3lpyAyaDIXb K60pClFMI+hTKtJGSH5KxIIg4LS58Exmls835ARKyU6IAXLIZjyEpfzKVZTwZ2da0d0X IFKg== X-Gm-Message-State: APjAAAXmKmIEEeeR1UCrrsaiAmKyzOWTNoMZZERVSd+ah4/LWcGOzH8k ahZeL2+7JKfaL9d76uAp73pA5erQZioaW3Ju5qc= X-Google-Smtp-Source: APXvYqwOO13A41HtjuUQe4sv4eu4rVgFn0OC5AVd9V0cE3MSGxeqRZPuKbTrJ/y4K1egU01KhMONsaCryETY/yND3W0= X-Received: by 2002:a92:831d:: with SMTP id f29mr31049248ild.263.1574636432052; Sun, 24 Nov 2019 15:00:32 -0800 (PST) MIME-Version: 1.0 References: <20191124154334.15366-1-leo.yan@linaro.org> In-Reply-To: <20191124154334.15366-1-leo.yan@linaro.org> From: Jeffrey Hugo Date: Sun, 24 Nov 2019 16:00:21 -0700 Message-ID: Subject: Re: [PATCH 1/2] tty: serial: msm_serial: Fix lockup for sysrq and oops To: Leo Yan Cc: Andy Gross , Greg Kroah-Hartman , Jiri Slaby , Bjorn Andersson , Stephen Boyd , Nicolas Dechesne , MSM , linux-serial@vger.kernel.org, lkml Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 24, 2019 at 8:44 AM Leo Yan wrote: > > As the commit 677fe555cbfb ("serial: imx: Fix recursive locking bug") > has mentioned the uart driver might cause recursive locking between > normal printing and the kernel debugging facilities (e.g. sysrq and > oops). In the commit it gave out suggestion for fixing recursive > locking issue: "The solution is to avoid locking in the sysrq case > and trylock in the oops_in_progress case." > > This patch follows the suggestion (also used the exactly same code with > other serial drivers, e.g. amba-pl011.c) to fix the recursive locking > issue, this can avoid stuck caused by deadlock and print out log for > sysrq and oops. > > Signed-off-by: Leo Yan Shouldn't this patch have a Fixes tag? Was there a cover letter?