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 36FCAC433F5 for ; Thu, 17 Feb 2022 03:48:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233027AbiBQDsz (ORCPT ); Wed, 16 Feb 2022 22:48:55 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:44670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229831AbiBQDsw (ORCPT ); Wed, 16 Feb 2022 22:48:52 -0500 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48421C0506; Wed, 16 Feb 2022 19:48:39 -0800 (PST) Received: by mail-io1-xd2a.google.com with SMTP id q8so2225543iod.2; Wed, 16 Feb 2022 19:48:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WgWVdTddSK1VIvJpihEOxrT4Mi3SIzAJw8C0VgfJ1+E=; b=PFLx2BNFItOcSBVBzOes2CcfuiOg9MZFNk4GMlp3FEWB8qTgBL5FbKnZoRAKYReNL/ ReDNJ2jxVfhXYWmadIOhteBp5jp1Sev1vNmsZeyjXjVlSxi4P2CC/txIQX7x9no42fno 35b9yd+0zjb90kjD0RTZWE4ze/Nt2mO0Dv2OBbNMV0VvkEHUdLIB1FJ8RryJH/Fwzuky RLM4b4LiDs6AJEA/W6MVIubgvSU1zPeT1bXXrH157OyjpS7EBS2G9qdbF4skflStaHXi nfMGkMcVbjqWYUHs2Td7/xiydiYvo50td+/vQ/lbFICW72LMNHR+7cwzpp61v9C8G6jN 5c0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WgWVdTddSK1VIvJpihEOxrT4Mi3SIzAJw8C0VgfJ1+E=; b=4nFyqzaluVju0um2nE9FK6QUhRvTEXSsrIybkjQhfv/UGaZApxeR/5OFh9FZycazfb 39cTG82c5vF8cKtYN7aVy8ed6huuWJ1q1ZizP7pUQLtHyW3MSQ6SoiscH+xqDO5aGM2N 36xXhpLglvI4siL7qnmiaw7ZrUKTCnM9zeCllT/sa2aaoCSQ51zqoN06OvjYvS1XZt8G DL2SbfTvs6uFdzkrJFx3NaQx0xZnsYbsHu5DPZGOUnwUTURNTOUr6uVXKP5Oje049d98 9Ptlu7lZA1Y1GqD7kbGXabX2DCsRSbXyTA94k03FOk6wN0Ctwe38MjEFtTlCL0bXB3tT i8zQ== X-Gm-Message-State: AOAM531lxSzH1BVQr3yzQ9SABg4bswQDgt9naQGHXzvXmz/eeeo9ZASc MHnaVlYjDsRhLrp44AOInow= X-Google-Smtp-Source: ABdhPJw368F4fr7QiyGQIds6VCL1NhGqtcNQKtxpD3CT5e3gMbNyzA1gjwbx4VI1KL4OErxP7BRLbw== X-Received: by 2002:a02:a808:0:b0:30e:e741:5457 with SMTP id f8-20020a02a808000000b0030ee7415457mr687157jaj.289.1645069718640; Wed, 16 Feb 2022 19:48:38 -0800 (PST) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:2010::1b19]) by smtp.googlemail.com with ESMTPSA id l16sm1127874ilc.54.2022.02.16.19.48.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Feb 2022 19:48:38 -0800 (PST) From: Jim Cromie To: jbaron@akamai.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: daniel.vetter@ffwll.ch, seanpaul@chromium.org, robdclark@gmail.com, linux@rasmusvillemoes.dk, joe@perches.com, Jim Cromie , vincent.whitchurch@axis.com, stable@vger.kernel.org Subject: [PATCH 01/13] dyndbg: fix static_branch manipulation Date: Wed, 16 Feb 2022 20:48:17 -0700 Message-Id: <20220217034829.64395-2-jim.cromie@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220217034829.64395-1-jim.cromie@gmail.com> References: <20220217034829.64395-1-jim.cromie@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In https://lore.kernel.org/lkml/20211209150910.GA23668@axis.com/ Vincent's patch commented on, and worked around, a bug toggling static_branch's, when a 2nd PRINTK-ish flag was added. The bug results in a premature static_branch_disable when the 1st of 2 flags was disabled. The cited commit computed newflags, but then in the JUMP_LABEL block, did not use that result, but used just one of the terms in it. Using newflags instead made the code work properly. This is Vincents test-case, reduced. It needs the 2nd flag to work properly, but it's explanatory here. pt_test() { echo 5 > /sys/module/dynamic_debug/verbose site="module tcp" # just one callsite echo " $site =_ " > /proc/dynamic_debug/control # clear it # A B ~A ~B for flg in +T +p "-T #broke here" -p; do echo " $site $flg " > /proc/dynamic_debug/control done; # A B ~B ~A for flg in +T +p "-p #broke here" -T; do echo " $site $flg " > /proc/dynamic_debug/control done } pt_test Fixes: 84da83a6ffc0 dyndbg: combine flags & mask into a struct, simplify with it CC: vincent.whitchurch@axis.com CC: stable@vger.kernel.org Signed-off-by: Jim Cromie --- lib/dynamic_debug.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index dd7f56af9aed..a56c1286ffa4 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -211,10 +211,11 @@ static int ddebug_change(const struct ddebug_query *query, continue; #ifdef CONFIG_JUMP_LABEL if (dp->flags & _DPRINTK_FLAGS_PRINT) { - if (!(modifiers->flags & _DPRINTK_FLAGS_PRINT)) + if (!(newflags & _DPRINTK_FLAGS_PRINT)) static_branch_disable(&dp->key.dd_key_true); - } else if (modifiers->flags & _DPRINTK_FLAGS_PRINT) + } else if (newflags & _DPRINTK_FLAGS_PRINT) { static_branch_enable(&dp->key.dd_key_true); + } #endif dp->flags = newflags; v4pr_info("changed %s:%d [%s]%s =%s\n", -- 2.35.1