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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Paul Mackerras <paulus@samba.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org, Ingo Molnar <mingo@kernel.org>
Subject: [for-next][PATCH 05/24] powerpc/frace: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack
Date: Fri, 21 Dec 2018 12:56:23 -0500	[thread overview]
Message-ID: <20181221175656.041890777@goodmis.org> (raw)
In-Reply-To: 20181221175618.968519903@goodmis.org

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/powerpc/kernel/process.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 96f34730010f..ce393df243aa 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2061,9 +2061,10 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	int count = 0;
 	int firstframe = 1;
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	int curr_frame = current->curr_ret_stack;
+	struct ftrace_ret_stack *ret_stack;
 	extern void return_to_handler(void);
 	unsigned long rth = (unsigned long)return_to_handler;
+	int curr_frame = 0;
 #endif
 
 	sp = (unsigned long) stack;
@@ -2089,9 +2090,13 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 			printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 			if ((ip == rth) && curr_frame >= 0) {
-				pr_cont(" (%pS)",
-				       (void *)current->ret_stack[curr_frame].ret);
-				curr_frame--;
+				ret_stack = ftrace_graph_get_ret_stack(current,
+								  curr_frame++);
+				if (ret_stack)
+					pr_cont(" (%pS)",
+						(void *)ret_stack->ret);
+				else
+					curr_frame = -1;
 			}
 #endif
 			if (firstframe)
-- 
2.19.2



       reply	other threads:[~2018-12-21 18:00 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20181221175618.968519903@goodmis.org>
2018-12-21 17:56 ` Steven Rostedt [this message]
2018-12-22  9:51   ` [for-next][PATCH 05/24] powerpc/frace: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack Michael Ellerman
2018-12-22 12:24     ` Steven Rostedt

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