From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wout2-smtp.messagingengine.com ([64.147.123.25]:52599 "EHLO wout2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725888AbeLCK42 (ORCPT ); Mon, 3 Dec 2018 05:56:28 -0500 Subject: FAILED: patch "[PATCH] function_graph: Reverse the order of pushing the ret_stack" failed to apply to 4.4-stable tree To: rostedt@goodmis.org, mhiramat@kernel.org Cc: From: Date: Mon, 03 Dec 2018 11:55:52 +0100 Message-ID: <154383455213782@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 7c6ea35ef50810aa12ab26f21cb858d980881576 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 20 Nov 2018 12:40:25 -0500 Subject: [PATCH] function_graph: Reverse the order of pushing the ret_stack and the callback The function graph profiler uses the ret_stack to store the "subtime" and reuse it by nested functions and also on the return. But the current logic has the profiler callback called before the ret_stack is updated, and it is just modifying the ret_stack that will later be allocated (it's just lucky that the "subtime" is not touched when it is allocated). This could also cause a crash if we are at the end of the ret_stack when this happens. By reversing the order of the allocating the ret_stack and then calling the callbacks attached to a function being traced, the ret_stack entry is no longer used before it is allocated. Cc: stable@kernel.org Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 4f0d72ae6362..2561460d7baf 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -188,15 +188,17 @@ int function_graph_enter(unsigned long ret, unsigned long func, trace.func = func; trace.depth = ++current->curr_ret_depth; - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) - goto out; - if (ftrace_push_return_trace(ret, func, frame_pointer, retp)) goto out; + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) + goto out_ret; + return 0; + out_ret: + current->curr_ret_stack--; out: current->curr_ret_depth--; return -EBUSY;