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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT 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 32722C433DF for ; Wed, 3 Jun 2020 07:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CC3720679 for ; Wed, 3 Jun 2020 07:22:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="qZkL/mXJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725888AbgFCHWg (ORCPT ); Wed, 3 Jun 2020 03:22:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725828AbgFCHWf (ORCPT ); Wed, 3 Jun 2020 03:22:35 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53E5FC05BD43 for ; Wed, 3 Jun 2020 00:22:35 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id t7so1176835pgt.3 for ; Wed, 03 Jun 2020 00:22:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=sFHwcYSPIAh2Jj0qa/cpOPKVZENd3AGMzBBQqYwi8fI=; b=qZkL/mXJwIrnssnR3nwvS3ogWwJlwkBYYLFqCM55iFXgsyN7HTcPXZUnnPva+TApSP bA7x95Rvwp4TX/juPI2tBvWmKu5YF3jxWj/gSA58Lr7mHnqWVYVdNgJhn6nE3o8Ecfwr npProNTKjX/dsjTkgGDDvqTHTqoyhLRBIErCIUSRLB2werNOi08K4tcchexeQ8f1471y f1YNmAy/Rio8g/eW0AJCxZUvtyW3fCbR2hPzNOI6klOs66EInWZMwShTRclGqgqOGLg8 Mh3WWS0EMOYFeTVkywYELtS4khgEN4MsB/rWhXIR/pt5DjaG3AD/7ke852VtjS41H0fb aZgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=sFHwcYSPIAh2Jj0qa/cpOPKVZENd3AGMzBBQqYwi8fI=; b=tkKvX/Gd8ZM48nCSkUjj9Qii3nd9gvIvqIMojjq4FoNvW2cQbYk01Mw1Iw9YB2Zmuk BkvtfuHr66N3LhUMAnYFFB3jK2am9SBtyBfTEaYDRAnGZNR78fixOBtilOTxYrVjlgg/ rxBW/uFcFCOs1+4XKT0cS3aCejZKDDRsHg+nq+eH3V5HkccMg7P516pAenVdoSLt5XE/ 4MYQgg2ohjwrUQ4bjtnyMFQl7noqg2mtW6xfKTFo6TC4i6ux9DnOkbwaPntm2ASo9UgQ B+On1iTVUbz/sgx5+DSdND/Ua4VR13vxbwA2knuWH4feJBmbH0sf9fx4fJEKnTrrqcIu YXqg== X-Gm-Message-State: AOAM530w/p67ics+B6iN22TilqBRiW+19CjKXBfPa++9KdoA3WzmqXzp 0Ay3wWsrM/NCiuqo1ShnHaVA3g== X-Google-Smtp-Source: ABdhPJzYrtSuBzWBxQeHuhyPGoIWSMJmm2YZ33qvTuLmq1Kfeq7Iqz/43WDaMW+sx+et84376Qck9g== X-Received: by 2002:a63:4c1f:: with SMTP id z31mr26862932pga.143.1591168954526; Wed, 03 Jun 2020 00:22:34 -0700 (PDT) Received: from localhost.localdomain ([117.252.66.248]) by smtp.gmail.com with ESMTPSA id j17sm1407272pjy.22.2020.06.03.00.22.29 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 03 Jun 2020 00:22:33 -0700 (PDT) From: Sumit Garg To: daniel.thompson@linaro.org Cc: kgdb-bugreport@lists.sourceforge.net, jason.wessel@windriver.com, dianders@chromium.org, pmladek@suse.com, sergey.senozhatsky@gmail.com, gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org, Sumit Garg Subject: [PATCH v5 0/4] kdb: Improve console handling Date: Wed, 3 Jun 2020 12:52:11 +0530 Message-Id: <1591168935-6382-1-git-send-email-sumit.garg@linaro.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch-set is aimed to improve console handling especially when kdb operates in NMI context. Brief description of enhancements: - Add status check for console prior to invoking corresponding handler. - Fixup to avoid possible deadlock in NMI context due to usage of locks in the console handlers. - Prefer usage of polling I/O driver mode (lockless APIs) over invocation of console handlers. Changes in v5: - Rebased on top of tags/kgdb-5.8-rc1. - Get rid of kdb_io_write(). - Fixed issue reported by kbuild test robot. - Remove is_console from kgdboc_earlycon_io_ops as well. - Misc. comments. - Added Doug's review tag. Changes in v4: - Use dbg_io_ops->write_char() directly instead of passing it as a function pointer. - Use "struct console" rather than "struct tty_driver" for comparison. - Make commit descriptions and comments more informative. - Add review tag for patch #2. Changes in v3: - Split patch to have separate patch for console status check. - New patch to re-factor kdb message emit code. - New patch to prefer polling I/O over console mode. - Add code comments to describe usage of oops_in_progress. Changes in v2: - Use oops_in_progress directly instead of bust_spinlocks(). Sumit Garg (4): kdb: Re-factor kdb_printf() message write code kdb: Check status of console prior to invoking handlers kdb: Make kdb_printf() console handling more robust kdb: Switch to use safer dbg_io_ops over console APIs drivers/tty/serial/kgdb_nmi.c | 2 +- drivers/tty/serial/kgdboc.c | 6 ++-- drivers/usb/early/ehci-dbgp.c | 3 +- include/linux/kgdb.h | 5 ++- kernel/debug/kdb/kdb_io.c | 72 ++++++++++++++++++++++++++----------------- 5 files changed, 51 insertions(+), 37 deletions(-) -- 2.7.4