From 6d6150bffbc74f7d9dca9e02b3b301282db63168 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 11 Feb 2016 22:06:28 +0100
Subject: [PATCH 307/365] kernel: sched: Fix preempt_disable_ip recodring for
 preempt_disable()

preempt_disable() invokes preempt_count_add() which saves the caller in
current->preempt_disable_ip. It uses CALLER_ADDR1 which does not look for its
caller but for the parent of the caller. Which means we get the correct caller
for something like spin_lock() unless the architectures inlines those
invocations. It is always wrong for preempt_disable() or local_bh_disable().

This patch makes the function get_parent_ip() which tries CALLER_ADDR0,1,2 if
the former is a locking function.  This seems to record the preempt_disable()
caller properly for preempt_disable() itself as well as for get_cpu_var() or
local_bh_disable().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/linux/ftrace.h | 12 ++++++++++++
 include/linux/sched.h  |  2 --
 kernel/sched/core.c    | 14 ++------------
 kernel/softirq.c       |  4 ++--
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 60048c50404e..f2cd67624f18 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -694,6 +694,18 @@ static inline void __ftrace_enabled_restore(int enabled)
 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 
+static inline unsigned long get_lock_parent_ip(void)
+{
+	unsigned long addr = CALLER_ADDR0;
+
+	if (!in_lock_functions(addr))
+		return addr;
+	addr = CALLER_ADDR1;
+	if (!in_lock_functions(addr))
+		return addr;
+	return CALLER_ADDR2;
+}
+
 #ifdef CONFIG_IRQSOFF_TRACER
   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index fef7756f8fda..3954565fe4a6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -183,8 +183,6 @@ extern void update_cpu_load_nohz(void);
 static inline void update_cpu_load_nohz(void) { }
 #endif
 
-extern unsigned long get_parent_ip(unsigned long addr);
-
 extern void dump_cpu_task(int cpu);
 
 struct seq_file;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c028e47b9afd..4b9de3446fa0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3064,16 +3064,6 @@ u64 scheduler_tick_max_deferment(void)
 }
 #endif
 
-notrace unsigned long get_parent_ip(unsigned long addr)
-{
-	if (in_lock_functions(addr)) {
-		addr = CALLER_ADDR2;
-		if (in_lock_functions(addr))
-			addr = CALLER_ADDR3;
-	}
-	return addr;
-}
-
 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
 				defined(CONFIG_PREEMPT_TRACER))
 
@@ -3095,7 +3085,7 @@ void preempt_count_add(int val)
 				PREEMPT_MASK - 10);
 #endif
 	if (preempt_count() == val) {
-		unsigned long ip = get_parent_ip(CALLER_ADDR1);
+		unsigned long ip = get_lock_parent_ip();
 #ifdef CONFIG_DEBUG_PREEMPT
 		current->preempt_disable_ip = ip;
 #endif
@@ -3122,7 +3112,7 @@ void preempt_count_sub(int val)
 #endif
 
 	if (preempt_count() == val)
-		trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
 	__preempt_count_sub(val);
 }
 EXPORT_SYMBOL(preempt_count_sub);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 2ca63cc1469e..cb9c1d5dee10 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -287,9 +287,9 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
 
 	if (preempt_count() == cnt) {
 #ifdef CONFIG_DEBUG_PREEMPT
-		current->preempt_disable_ip = get_parent_ip(CALLER_ADDR1);
+		current->preempt_disable_ip = get_lock_parent_ip();
 #endif
-		trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+		trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip());
 	}
 }
 EXPORT_SYMBOL(__local_bh_disable_ip);
-- 
2.10.2

