From patchwork Mon May 16 22:56:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Cromie X-Patchwork-Id: 573030 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 10D0FC43217 for ; Mon, 16 May 2022 22:57:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349806AbiEPW5D (ORCPT ); Mon, 16 May 2022 18:57:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349862AbiEPW5A (ORCPT ); Mon, 16 May 2022 18:57:00 -0400 Received: from mail-il1-x12c.google.com (mail-il1-x12c.google.com [IPv6:2607:f8b0:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EECF664D1; Mon, 16 May 2022 15:56:56 -0700 (PDT) Received: by mail-il1-x12c.google.com with SMTP id s12so8934441iln.11; Mon, 16 May 2022 15:56:56 -0700 (PDT) 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=cpRV3Wk55836kFETyr3P+oiMpdiGkRAymJ30pnxlc/A=; b=QWDky+6aYSWTOwbaXHfQ0qh88ZnwyW0nlRYt7AFIGi+pr/O7HtcDIZJoUwY2uQliu9 5DAnS8pAk7ltR19hsFx8xD11J2e9C34b2EjKu7G6GZifsv++3x/PCoYhmSfc/jI82CXO JUEUoEtDBZ7pN9W2qjVFdRQisajSDDRF9gBcGxncCVHpLUX9MVMMQrf7oBR96vEAgw3v G1Vvu/OQQjiiWdQZCJFaUgvE5rJQOlDtXzKaHx5ANWL3e16JKqk/EXa4Id3glwwNsY4o WuevVJX9Rtx87k0vFCNdiF7BW2MjYUmONfgUNWzT6G14Gl158geu3MfQqxnhhv8rS5mn OMsg== 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=cpRV3Wk55836kFETyr3P+oiMpdiGkRAymJ30pnxlc/A=; b=KhuthDJ2PGd9ZpiW01lHNB+YYcvXQttJrTBOEOscGfCfKIXq6KNxK3rsisHFAPRCfV mEsBX/x9+eD17a28sIhtkD1Q6nMNMSR+/Hy+eoEwh7k8ltXT4uIxIltkl4JDELD/b+TV Z6B45NCNFJg5MTEcMvw8abZgwAzodKGEbYKSIW/aK7mPOabtTxX1i1wdV5FLkMOCIbkk orgU7PATv754d8HUu8E2Ifg0mc3LrF5YmmJc8oPy2NPofJw6z0XwER619Mxu0+Gw0XMG WjfR4ed6rOBhg2RxDqZVZLP/G3qt93wHskdXiqor8cPduZoSuaaMFB28uHX6Zs6tEzjS Zq3A== X-Gm-Message-State: AOAM530iAYra1bQVY9CGBpFwWgbA8iuag3gOKKrYPMogT4C93915eYGq Kzt4OMiuPnhfFY1PCz6MUx4= X-Google-Smtp-Source: ABdhPJxZQnf4PMb/pE6aahB0jrFIkVLr5qLnxheVKq6wugGMIzNly4UwftUMV/XycUHdiBmfQ/0yIQ== X-Received: by 2002:a05:6e02:190c:b0:2cf:31b2:b0f7 with SMTP id w12-20020a056e02190c00b002cf31b2b0f7mr10351042ilu.46.1652741816349; Mon, 16 May 2022 15:56:56 -0700 (PDT) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:2010::dd9f]) by smtp.googlemail.com with ESMTPSA id k26-20020a02661a000000b0032b74686763sm3133949jac.76.2022.05.16.15.56.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 May 2022 15:56:55 -0700 (PDT) From: Jim Cromie To: jbaron@akamai.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: gregkh@linuxfoundation.org, daniel.vetter@ffwll.ch, seanpaul@chromium.org, robdclark@gmail.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, quic_saipraka@quicinc.com, will@kernel.org, catalin.marinas@arm.com, quic_psodagud@quicinc.com, maz@kernel.org, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, mingo@redhat.com, jim.cromie@gmail.com, vincent.whitchurch@axis.com, Jason Baron Subject: [PATCH v2 01/27] dyndbg: fix static_branch manipulation Date: Mon, 16 May 2022 16:56:14 -0600 Message-Id: <20220516225640.3102269-2-jim.cromie@gmail.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220516225640.3102269-1-jim.cromie@gmail.com> References: <20220516225640.3102269-1-jim.cromie@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@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 demonstrate the bug, 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 Acked-by: Jason Baron --- .drop @stable, no exposed bug. .add jbaron ack --- 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",