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 X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECC6DC282C4 for ; Tue, 12 Feb 2019 21:42:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B405D222C0 for ; Tue, 12 Feb 2019 21:42:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=rasmusvillemoes.dk header.i=@rasmusvillemoes.dk header.b="iSZ2ZAQI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731775AbfBLVmH (ORCPT ); Tue, 12 Feb 2019 16:42:07 -0500 Received: from mail-ed1-f68.google.com ([209.85.208.68]:43081 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731057AbfBLVmF (ORCPT ); Tue, 12 Feb 2019 16:42:05 -0500 Received: by mail-ed1-f68.google.com with SMTP id f9so146660eds.10 for ; Tue, 12 Feb 2019 13:42:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=c/DP+/WPa+Jq+JAZdR/A0ANzlyTG7UQQ0eBVWCTtWwc=; b=iSZ2ZAQIrQiu4zvswrqxRbv/hOc15iZsZHSIg0qRcuB7IlbKMG8RWvp+MgAUlw7VOo VSzLPYMyKNl873vKJOyKjjodhd/QC3DaAgrIE8m4UPnreR5SYyA8sn8puWcD8mvxSFSS yVIeIuKbBGx6/r/lyrPdmGoLzAY13QaB5xy0M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=c/DP+/WPa+Jq+JAZdR/A0ANzlyTG7UQQ0eBVWCTtWwc=; b=XcGEFptonzj1JxdBgwlSfpKDFs3WRnGNJnBgpiR3Hhac8TFK04WFaLrz0gzGgmV9W/ zHaO/S63AlFGIsHZdn2XpZeFyI444njKEqTrJJ5SvUBFH3hJtTCttMUpClskdOd0U++V CcYQ820stYwI6N1pzmQHf3jLUv3vC5J7icWD24uVQNVinV79k/COJYG4dInn2pJO1fXB pl1pYdU09Axm5IUeeDK9QOHm5lX3/yVoSzRW+o0X9LaGvDaET/WAb7K7/mWRaVu4HgQg OHKJ2cyNl0shzuk43PZqNn55yWyZlbEI3pzHNb7G0zf5pNiD8vzNcZSpILUoV5GPdSh6 BUjw== X-Gm-Message-State: AHQUAubQUBEuR6mlDKaDw4npipPdDYwBNDLw7Re0kXjqDUp+Mi/fZPQB lIoQHst1gfK4HLbzNQPLASXk5g== X-Google-Smtp-Source: AHgI3Ialyaz6Q4vU9n5eHDQiT/dIOOvq67rwbx4q4+Yb9jl0YIdK6BqnB1JHWIT0VIiVF7okO4ZtgQ== X-Received: by 2002:a17:906:4306:: with SMTP id j6mr4229872ejm.174.1550007723363; Tue, 12 Feb 2019 13:42:03 -0800 (PST) Received: from prevas-ravi.waoo.dk (ip-5-186-119-174.cgn.fibianet.dk. [5.186.119.174]) by smtp.gmail.com with ESMTPSA id v1sm3697607eds.47.2019.02.12.13.42.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Feb 2019 13:42:02 -0800 (PST) From: Rasmus Villemoes To: Andrew Morton , Jason Baron Cc: linux-kernel@vger.kernel.org, Rasmus Villemoes Subject: [PATCH v4 06/14] dynamic_debug: use pointer comparison in ddebug_remove_module Date: Tue, 12 Feb 2019 22:41:42 +0100 Message-Id: <20190212214150.4807-7-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190212214150.4807-1-linux@rasmusvillemoes.dk> References: <20190212214150.4807-1-linux@rasmusvillemoes.dk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that we store the passed-in string directly in ddebug_add_module, we can use pointer equality instead of strcmp. This is a little more efficient, but more importantly, this also makes the code somewhat more correct: Currently, if one loads and then unloads a module whose name happens to match the KBUILD_MODNAME of some built-in functionality (which need not even be modular at all), all of their dynamic debug entries vanish along with those of the actual module. For example, loading and unloading a core.ko hides all pr_debugs from drivers/base/core.c and other built-in files called core.c (incidentally, there is an in-tree module whose name is core, but I just tested this with an out-of-tree trivial one). Acked-by: Jason Baron Signed-off-by: Rasmus Villemoes --- lib/dynamic_debug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 8274c4ea75e0..214828c65625 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -929,9 +929,10 @@ int ddebug_remove_module(const char *mod_name) mutex_lock(&ddebug_lock); list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) { - if (!strcmp(dt->mod_name, mod_name)) { + if (dt->mod_name == mod_name) { ddebug_table_free(dt); ret = 0; + break; } } mutex_unlock(&ddebug_lock); -- 2.20.1