From nobody Fri Dec 19 16:01:38 2025 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 89F29C04A95 for ; Sat, 22 Oct 2022 10:14:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230216AbiJVKO2 (ORCPT ); Sat, 22 Oct 2022 06:14:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230300AbiJVKOB (ORCPT ); Sat, 22 Oct 2022 06:14:01 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 412EAB03FB; Sat, 22 Oct 2022 02:31:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 07534CE2CAC; Sat, 22 Oct 2022 07:53:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8C3BC433C1; Sat, 22 Oct 2022 07:52:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666425180; bh=4wv5WtR//CDdsvxu8xL/5g2O2bXmliW8UL1zS+PsHLM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wpa1+Tmadnty8pzd3Gn6oYmMvMjwJzv7T/ZaZV2h0nEbNbKY0qAh5qC9frEhG2s+g xEzLIu/oTim3kMaur0cBjECfkPhin0tEtgNUz2I4Cr54IEDOUf/CRuM0g5+KRwXwO2 Tw7rEk15gOypjVLYIWMt/fvDzAn7Omz+d9TSYb+g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, vincent.whitchurch@axis.com, Jason Baron , Daniel Vetter , Jim Cromie , Sasha Levin Subject: [PATCH 5.19 417/717] dyndbg: fix static_branch manipulation Date: Sat, 22 Oct 2022 09:24:56 +0200 Message-Id: <20221022072516.673209048@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221022072415.034382448@linuxfoundation.org> References: <20221022072415.034382448@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jim Cromie [ Upstream commit ee879be38bc87f8cedc79ae2742958db6533ca59 ] 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=3D"module tcp" # just one callsite echo " $site =3D_ " > /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 wi= th it CC: vincent.whitchurch@axis.com Acked-by: Jason Baron Acked-by: Daniel Vetter Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-2-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- 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 *q= uery, 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 =3D newflags; v4pr_info("changed %s:%d [%s]%s =3D%s\n", --=20 2.35.1