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 C7315C43219 for ; Wed, 23 Nov 2022 10:08:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236565AbiKWKIG (ORCPT ); Wed, 23 Nov 2022 05:08:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236879AbiKWKGq (ORCPT ); Wed, 23 Nov 2022 05:06:46 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED79413CEE for ; Wed, 23 Nov 2022 01:57:23 -0800 (PST) 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 8B7FA61B29 for ; Wed, 23 Nov 2022 09:57:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72A3DC433C1; Wed, 23 Nov 2022 09:57:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669197443; bh=MFevkjK4Km5E5MgdatlZan6/En6MRZnPBJO5ogmUvr4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YWmsYsxU5nEOkcBFN1LXrg6qHvvqF64O4Aw/cle1QWdZ9euU7iioflSczLBiMMnCZ NGcnXBxI/85HjXcGc4ymSXppmcON3kaiMIwqF1GiHivIt2RA4nbmxGjryXheqhyWLB Zo4l+9AiIgkwJj+dfOe5ZCbg47lli8P+TT/OvoCU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zheng Yejian , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.0 295/314] tracing: Fix potential null-pointer-access of entry in list tr->err_log Date: Wed, 23 Nov 2022 09:52:20 +0100 Message-Id: <20221123084638.893376943@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084625.457073469@linuxfoundation.org> References: <20221123084625.457073469@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: stable@vger.kernel.org From: Zheng Yejian [ Upstream commit 067df9e0ad48a97382ab2179bbe773a13a846028 ] Entries in list 'tr->err_log' will be reused after entry number exceed TRACING_LOG_ERRS_MAX. The cmd string of the to be reused entry will be freed first then allocated a new one. If the allocation failed, then the entry will still be in list 'tr->err_log' but its 'cmd' field is set to be NULL, later access of 'cmd' is risky. Currently above problem can cause the loss of 'cmd' information of first entry in 'tr->err_log'. When execute `cat /sys/kernel/tracing/error_log`, reproduce logs like: [ 37.495100] trace_kprobe: error: Maxactive is not for kprobe(null) ^ [ 38.412517] trace_kprobe: error: Maxactive is not for kprobe Command: p4:myprobe2 do_sys_openat2 ^ Link: https://lore.kernel.org/linux-trace-kernel/20221114104632.3547266-1-zhengyejian1@huawei.com Fixes: 1581a884b7ca ("tracing: Remove size restriction on tracing_log_err cmd strings") Signed-off-by: Zheng Yejian Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/trace.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 87d2f04152f9..7132e21e90d6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7803,6 +7803,7 @@ static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr, int len) { struct tracing_log_err *err; + char *cmd; if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) { err = alloc_tracing_log_err(len); @@ -7811,12 +7812,12 @@ static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr, return err; } - + cmd = kzalloc(len, GFP_KERNEL); + if (!cmd) + return ERR_PTR(-ENOMEM); err = list_first_entry(&tr->err_log, struct tracing_log_err, list); kfree(err->cmd); - err->cmd = kzalloc(len, GFP_KERNEL); - if (!err->cmd) - return ERR_PTR(-ENOMEM); + err->cmd = cmd; list_del(&err->list); return err; -- 2.35.1