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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 065FAC43381 for ; Sat, 16 Feb 2019 11:19:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA3D2222DD for ; Sat, 16 Feb 2019 11:19:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729416AbfBPLTM (ORCPT ); Sat, 16 Feb 2019 06:19:12 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:3222 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725294AbfBPLTL (ORCPT ); Sat, 16 Feb 2019 06:19:11 -0500 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 8040581B00B149F3FA97; Sat, 16 Feb 2019 19:19:09 +0800 (CST) Received: from [127.0.0.1] (10.177.244.145) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.408.0; Sat, 16 Feb 2019 19:19:03 +0800 Subject: Re: [PATCH] tracing: fix incorrect tracer freeing when opening tracing pipe To: Steven Rostedt References: <1550060946-45984-1-git-send-email-yi.zhang@huawei.com> <20190213083635.36f4762e@gandalf.local.home> CC: , , From: "zhangyi (F)" Message-ID: Date: Sat, 16 Feb 2019 19:19:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20190213083635.36f4762e@gandalf.local.home> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.177.244.145] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/2/13 21:36, Steven Rostedt Wrote: > On Wed, 13 Feb 2019 20:29:06 +0800 > "zhangyi (F)" wrote: > >> Commit d716ff71dd12 ("tracing: Remove taking of trace_types_lock in >> pipe files") use the current tracer instead of the copy in >> tracing_open_pipe(), but it forget to remove the freeing sentence in >> the error path. >> >> Fixes: d716ff71dd12 ("tracing: Remove taking of trace_types_lock in pipe files") > > Thanks. > > As this is harmless (frees to NULL is ok, and iter is allocated with > kzalloc()), I'm going to just add this for the next merge window. > This patch patch want to remove kfree(iter->trace) instead of kfree(iter), which is set by tr->current_trace and probably not allocated dynamically. So if we kfree such tracer in the error path, it will lead to BUG_ON. Thanks， Yi. > >> Signed-off-by: zhangyi (F) >> --- >> kernel/trace/trace.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c >> index c521b73..b583ff7 100644 >> --- a/kernel/trace/trace.c >> +++ b/kernel/trace/trace.c >> @@ -5624,7 +5624,6 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) >> return ret; >> >> fail: >> - kfree(iter->trace); >> kfree(iter); >> __trace_array_put(tr); >> mutex_unlock(&trace_types_lock); > > > . >