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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 6E542C433E2 for ; Tue, 1 Sep 2020 09:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CCCA20866 for ; Tue, 1 Sep 2020 09:16:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726355AbgIAJQ6 (ORCPT ); Tue, 1 Sep 2020 05:16:58 -0400 Received: from mga18.intel.com ([134.134.136.126]:43991 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725848AbgIAJQ5 (ORCPT ); Tue, 1 Sep 2020 05:16:57 -0400 IronPort-SDR: zrGLjmyPgckUoXn88l/bZVn14Cr5dlIayoGO5fjPXxNj3F5kkVAWMMN6eFBL4GjoVOToFpdLqG oPiZHkR9ZbAw== X-IronPort-AV: E=McAfee;i="6000,8403,9730"; a="144822918" X-IronPort-AV: E=Sophos;i="5.76,378,1592895600"; d="scan'208";a="144822918" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2020 02:16:56 -0700 IronPort-SDR: Oz1m7qzTotfs0rTVoLBMxMajC8WpaVm2W+PN5ACwHrBpXuZ47pQlLayhVgtMcESdrVo6YKUvGx DO3qptCGP9zA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,378,1592895600"; d="scan'208";a="283343284" Received: from ahunter-desktop.fi.intel.com ([10.237.72.73]) by fmsmga008.fm.intel.com with ESMTP; 01 Sep 2020 02:16:54 -0700 From: Adrian Hunter To: peterz@infradead.org, rostedt@goodmis.org Cc: mingo@redhat.com, mhiramat@kernel.org, mbenes@suse.cz, linux-kernel@vger.kernel.org Subject: [PATCH] ftrace: Fix missing synchronize_rcu() removing trampoline from kallsyms Date: Tue, 1 Sep 2020 12:16:17 +0300 Message-Id: <20200901091617.31837-1-adrian.hunter@intel.com> X-Mailer: git-send-email 2.17.1 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add synchronize_rcu() after list_del_rcu() in ftrace_remove_trampoline_from_kallsyms() to protect readers of ftrace_ops_trampoline_list (in ftrace_get_trampoline_kallsym) which is used when kallsyms is read. Fixes: fc0ea795f53c8d ("ftrace: Add symbols for ftrace trampolines") Signed-off-by: Adrian Hunter --- kernel/trace/ftrace.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 275441254bb5..4e64367c9774 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2782,6 +2782,7 @@ static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops) { lockdep_assert_held(&ftrace_lock); list_del_rcu(&ops->list); + synchronize_rcu(); } /* -- 2.17.1