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 8B91BFA373E for ; Mon, 24 Oct 2022 14:23:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236891AbiJXOXg (ORCPT ); Mon, 24 Oct 2022 10:23:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235758AbiJXOV7 (ORCPT ); Mon, 24 Oct 2022 10:21:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15C88D0CD6; Mon, 24 Oct 2022 05:58:44 -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 dfw.source.kernel.org (Postfix) with ESMTPS id BDC19612E1; Mon, 24 Oct 2022 12:47:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A39B1C433C1; Mon, 24 Oct 2022 12:47:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666615639; bh=g2Fm0I3RQejCSozGXWCq1hr/XeMtu0MQASCSx31teHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MPK5JF6d+dawQemxVLpSuOxd59TCNcbjbUUk1RZ9ZIpaF5/nfV866m8ebbkvknmPm we8W+5cO9UMJr4KZqe3LLtTo44HFobMQYKJTqw6s9/j0pZaCjrU/hXfeEf6xcKLwQE +lIoPGijlrmQc3jNACJj2qDL4HfckAJO364JB9h0= 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 5.15 297/530] dyndbg: fix static_branch manipulation Date: Mon, 24 Oct 2022 13:30:41 +0200 Message-Id: <20221024113058.510839876@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113044.976326639@linuxfoundation.org> References: <20221024113044.976326639@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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="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 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 84c16309cc63..00e6507972d8 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -207,10 +207,11 @@ 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; v2pr_info("changed %s:%d [%s]%s =%s\n", -- 2.35.1