3.14.61-rt64-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bige...@linutronix.de>
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 <bige...@linutronix.de>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
include/linux/ftrace.h | 12 ++++++++++++
include/linux/sched.h | 2 --
kernel/sched/core.c | 14 ++------------
kernel/softirq.c | 2 +-
4 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 2068dff8a2cc..a28c5dab7131 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -625,6 +625,18 @@ static inline void __ftrace_enabled_restore(int enabled)
# endif
#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
+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 9e6db231d0b9..f49fd086d5dc 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -180,8 +180,6 @@ extern unsigned long this_cpu_load(void);
extern void calc_global_load(unsigned long ticks);
extern void update_cpu_load_nohz(void);
-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 3825465fb1eb..5e86914f2d3c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2548,16 +2548,6 @@ 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))
@@ -2579,7 +2569,7 @@ void __kprobes 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
@@ -2605,7 +2595,7 @@ void __kprobes 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 250669395a5f..7abfdab644bd 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -288,7 +288,7 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int
cnt)
raw_local_irq_restore(flags);
if (preempt_count() == cnt)
- 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);
#endif /* CONFIG_TRACE_IRQFLAGS */
--
2.7.0
