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 450BAC433F5 for ; Tue, 1 Mar 2022 16:46:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236258AbiCAQrf (ORCPT ); Tue, 1 Mar 2022 11:47:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234469AbiCAQrb (ORCPT ); Tue, 1 Mar 2022 11:47:31 -0500 Received: from mail-il1-x129.google.com (mail-il1-x129.google.com [IPv6:2607:f8b0:4864:20::129]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A49ECDF9B; Tue, 1 Mar 2022 08:46:50 -0800 (PST) Received: by mail-il1-x129.google.com with SMTP id i1so6378516ilu.6; Tue, 01 Mar 2022 08:46:50 -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=ZyIqslhYvDH+znU49RDNGGBtdf2Hx25EKBLYyLNACYFixw48LAxXuDhuXdvN2vYeV0 XtVH31Chbhr2WBzD6kuN2Lz7Aq+1wtlZukZS0en4xgMbIdXnVLKXVxq/s8o5v54hvmbr +v/3ebOGaZG+QRjCOwG4LGK73r4S2U8Ik1iea312xRwkjMKD5XcO0+V3Zr5uaVlkFpZ6 hZJZ8yZ5Rh0tqRdJg4cL4zVkFORCWrFm1fmiKLAeBYsrqNKwmLTjrWspHnjSm+tRlfKv iW1YRmjCT7tc86d4IU91fXGtrPZWxgYvQhvUdvUCycWPlc8fa3md+RIZKr5NCtx0XegN W6+g== 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=zSj/hd/fcrYNj1xHMorLpVgBdVXVjtWKDDUOrSBx++E0rxYFa1G8o2Qj0NmqW29tBg viClcwLicV9RspMq2At6f7CwbRN3pbQxXMWqqfhgWLpFO76Pdm7EGrVNCvbadJdMWCsD oERUg6kcFtGL4Laxh0HKhb+UyS6coln/3Z1K/wdOgt2NN2L7FCYLUeLr+Z7q7Euzcbae ACHqnZcxvWvEU8jJx3YYt//nD9nW2JUahvlyAp5noAQHQgX7fkovon0HtBLQwWkPuRMG i7yFDpFaTxlPuqiq+dCfICbCsg/EFVyvtEQQe3qAnbvHEMs+VEdpeTPTIE1u3Z2UTbnG x1sQ== X-Gm-Message-State: AOAM532iELnAqsQv4PmcBm5gAweUoevM/WYBsJIvOEzTWSpk3+69k3wM rzIMAnb0podQWVKVHsmQxHw= X-Google-Smtp-Source: ABdhPJy2WosYoNk36kwc3YDo4CJeoXCvRi+g+pvs1KuGqtjA+5zI4UvsFnn0cAKS/KsQmhNn9fQ6aw== X-Received: by 2002:a05:6e02:1986:b0:2c4:804:2e6a with SMTP id g6-20020a056e02198600b002c408042e6amr2063617ilf.130.1646153210047; Tue, 01 Mar 2022 08:46:50 -0800 (PST) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:2010::f10e]) by smtp.googlemail.com with ESMTPSA id o3-20020a6b5a03000000b00640a33c5b0dsm7272411iob.17.2022.03.01.08.46.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Mar 2022 08:46:49 -0800 (PST) From: Jim Cromie To: jbaron@akamai.com, gregkh@linuxfoundation.org, daniel.vetter@ffwll.ch, seanpaul@chromium.org, robdclark@gmail.com, 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: Jim Cromie , vincent.whitchurch@axis.com, stable@vger.kernel.org Subject: [PATCH 01/13] dyndbg: fix static_branch manipulation Date: Tue, 1 Mar 2022 09:46:17 -0700 Message-Id: <20220301164629.3814634-2-jim.cromie@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220301164629.3814634-1-jim.cromie@gmail.com> References: <20220301164629.3814634-1-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