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 5032E2288C3; Wed, 11 Dec 2024 20:54:13 +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=1733950455; cv=none; b=PTxsU6BRVq7DFj9u0XS8ZwsoVMyxuuQSslme7/NewY8SFHwYlI8Mac1oxfnI86+uKQcgX7G0VvQnHqR6R1aa6lWQVomXMwF5RWFOPFw9XK8rciJudFZHmfbxPE6fL01sJYbN3FrLis28fjI0aqeanGPPC9xqBts/goS67wmTFnw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733950455; c=relaxed/simple; bh=qP+jw3reK6oo4+Arv7+zjxhygcwR7XDDrmzN/M1EP2A=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Lryjx3BkWr1o4f5gpuB4SK6izJluy2KqdcY2O3eFWNYiLefRGh/30tKUn/uoX9IptjsjsU42ReJFSo1zcPI6QoyLsNFcwltA5Anv0bjBh5g39K2rRMotZeKfAFvtNooTYchDTBY/wnKAdwsPAJAJohj9awguX5MLyZwgkeGCCj8= 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 EE61FC4CED2; Wed, 11 Dec 2024 20:54:12 +0000 (UTC) Date: Wed, 11 Dec 2024 15:54:11 -0500 From: Steven Rostedt To: LKML , Linux trace kernel Cc: Masami Hiramatsu , Mathieu Desnoyers , Al Viro , Michal Simek , Jeff Xie Subject: Re: [PATCH] ftrace/microblaze: Do not find "true_parent" for return address Message-ID: <20241211155411.46643bb9@batman.local.home> In-Reply-To: <20241211153634.69c75afa@batman.local.home> References: <20241211153634.69c75afa@batman.local.home> X-Mailer: Claws Mail 3.17.8 (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 [ Added Jeff ] -- Steve On Wed, 11 Dec 2024 15:36:34 -0500 Steven Rostedt wrote: > From: Steven Rostedt > > When function tracing and function graph tracing are both enabled (in > different instances) the "parent" of some of the function tracing events > is "return_to_handler" which is the trampoline used by function graph > tracing. To fix this, ftrace_get_true_parent_ip() was introduced that > returns the "true" parent ip instead of the trampoline. > > To do this, the ftrace_regs_get_stack_pointer() is used, which uses > kernel_stack_pointer(). The problem is that microblaze does not implement > kerenl_stack_pointer() so when function graph tracing is enabled, the > build fails. > > Modify the #ifdef check to the code around ftrace_get_true_parent_ip() to > include !defined(CONFIG_MICROBLAZE) which will default it to just return > the parent ip passed in, which may still be the ip of the function garph > trampoline. > > Fixes: 60b1f578b578 ("ftrace: Get the true parent ip for function tracer") > Reported-by: Al Viro > Signed-off-by: Steven Rostedt (Google) > --- > kernel/trace/trace_functions.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c > index 74c353164ca1..a75d107a45f8 100644 > --- a/kernel/trace/trace_functions.c > +++ b/kernel/trace/trace_functions.c > @@ -176,7 +176,8 @@ static void function_trace_start(struct trace_array *tr) > tracing_reset_online_cpus(&tr->array_buffer); > } > > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER > +/* Microblaze currently doesn't implement kernel_stack_pointer() */ > +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && !defined(CONFIG_MICROBLAZE) > static __always_inline unsigned long > function_get_true_parent_ip(unsigned long parent_ip, struct ftrace_regs *fregs) > {