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 9E7E9C433EF for ; Fri, 11 Mar 2022 04:48:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346389AbiCKEtZ (ORCPT ); Thu, 10 Mar 2022 23:49:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346227AbiCKEtT (ORCPT ); Thu, 10 Mar 2022 23:49:19 -0500 Received: from mail-il1-x12d.google.com (mail-il1-x12d.google.com [IPv6:2607:f8b0:4864:20::12d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBD8597293 for ; Thu, 10 Mar 2022 20:48:16 -0800 (PST) Received: by mail-il1-x12d.google.com with SMTP id r2so296813ilh.0 for ; Thu, 10 Mar 2022 20:48:16 -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=oAf0LosuiaLpXGtYs0EMjapukN/Wz4GaZEg3vD6y6ak=; b=FGomt3SpUqyItDxQTS6QatofCRhiZIi82c83FcZW5lAA7Hia4dUP0QS/5UI8s6V1iG p9ewH/E8qTORsPj4+OnlwfDOXUVrf8HA+fTwEUNyHVWnEW32jyMqS0HEMeua00mED9fG Jt5WhOje3GPSyOyvOMadpj6kIzq9ffhFw1is+8tPx5sOzNgcO1DanXFs7auqvAQR2OBg O5UhHrzIh8D2tX1MtSnEyQ5Xl0wYsAOwDwWqf53yNtM1nYFJb6c8e8muyyQDgIBl6Ddw xd1IC+TTQp3rkOr7C1IvU2aLj6DFtJpHblfIL1P1+F7+iR/oDHQO/VvQ8mZgMhLKEvdi yJug== 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=oAf0LosuiaLpXGtYs0EMjapukN/Wz4GaZEg3vD6y6ak=; b=hO6GHXaH+veNPN3qEZPTAs+u1k7nhpIGcxi5OzyuMfaE6HlgpC/lxULS5iD+DtAYvd sTiRNRtuSpfO8+QHo9r0/tT3XUpOP+D5CajapAIjaOFOT454VR4qrZK+JGOIRSd0+1qU 96Znnxe1o+3kTsngZFMGzEogQpcYaJsqxeslw7+8Ryo5jySj1ga+YqYYKzpvxnue3FU4 1SToHH/sSmPmTqM/KAY3ivh4vOE2wve2sw/88nqumvlBlB36ddMcBNale5hWfO7aBAnl GulDZTfEF19OzdZgvHt2GvtrXXAgYmtZIRM11e4NxR9Y0t6fuLoq4pa/rCVkgpNBgu0C JY3Q== X-Gm-Message-State: AOAM533oxc7U6me8QKPmoUIF/V7Dq7v5k79qxN3dQUtjxxXom874Kq2+ ScavoWIKoe+IPPCAwJZGut0= X-Google-Smtp-Source: ABdhPJwFZHg/BgFkwfNAHNLyEDOYNqmvUk/C+4ceSxeoTbqDRVietvJzifHbTMNcdfYqz0MT1Xo4PA== X-Received: by 2002:a05:6e02:1946:b0:2c7:730d:3e35 with SMTP id x6-20020a056e02194600b002c7730d3e35mr2075171ilu.179.1646974096273; Thu, 10 Mar 2022 20:48:16 -0800 (PST) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:2010::f10e]) by smtp.googlemail.com with ESMTPSA id q9-20020a5edb09000000b00645c7a00cbbsm3529834iop.20.2022.03.10.20.48.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Mar 2022 20:48:15 -0800 (PST) From: Jim Cromie To: jbaron@akamai.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org Cc: daniel.vetter@ffwll.ch, seanpaul@chromium.org, robdclark@gmail.com, linux@rasmusvillemoes.dk, joe@perches.com, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Jim Cromie , vincent.whitchurch@axis.com Subject: [PATCH 1/5] dyndbg: fix static_branch manipulation Date: Thu, 10 Mar 2022 21:47:52 -0700 Message-Id: <20220311044756.425777-2-jim.cromie@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220311044756.425777-1-jim.cromie@gmail.com> References: <20220311044756.425777-1-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, failed to use that result, instead using 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 Signed-off-by: Jim Cromie -- .drop @stable, no exposed bug. --- 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