From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B01C1A9B5A; Wed, 20 Nov 2024 14:51:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732114311; cv=none; b=luwAY+ashwCwnKE1y8objz1CnclJWzmtGyYiqKHiI2g45meZLXspwYkl/jQWz6PPkeXK2Aim/UZTfH7w0CHowprcPOYcFplV9ioSPXc1+yY2/AU0bzCovkRdn4IN62qcBZPE4wVFdGfmilgwR096mibVCcW/uILIiNlrgX+HyIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732114311; c=relaxed/simple; bh=U+A6YOKxmhKh1xHUKOJMiURI3ezd9XaHKZIkgUass3c=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Ws+6HIXFDezmkuoskM6e+kdysBvaEfD3vEGan2B//dD2fZigi6bCuGNrAJrX9nF/lXf3+TI6Vei+lf3M/KhHh1jb1MSWbgoXX+l9X2YO0Ms/fsrjBKwc2z7kqbhZnSjpSYQ8ULf25i+pJJleo92TXZH5OqEJZaqrWPVWMfLFq4k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 369ACC4CECD; Wed, 20 Nov 2024 14:51:50 +0000 (UTC) Date: Wed, 20 Nov 2024 09:52:25 -0500 From: Steven Rostedt To: guoweikang Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH] ftrace: Fix regression with module command in stack_trace_filter Message-ID: <20241120095225.37fe4655@gandalf.local.home> In-Reply-To: <20241120052750.275463-1-guoweikang.kernel@gmail.com> References: <20241120052750.275463-1-guoweikang.kernel@gmail.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 20 Nov 2024 13:27:49 +0800 guoweikang wrote: > When executing the following command: > > # echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter > > The current mod command causes a null pointer dereference. While commit > 0f17976568b3f ("ftrace: Fix regression with module command in stack_trace_filter") > has addressed part of the issue, it left a corner case unhandled, which still > results in a kernel crash. Ouch! Thanks, I'll also mark this as stable. -- Steve > > Signed-off-by: guoweikang > --- > kernel/trace/ftrace.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 71e53eaba8bc..9b17efb1a87d 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -5093,6 +5093,9 @@ ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash, > char *func; > int ret; > > + if (!tr) > + return -ENODEV; > + > /* match_records() modifies func, and we need the original */ > func = kstrdup(func_orig, GFP_KERNEL); > if (!func)