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sched/debug: Fix preempt_disable_ip recording for preempt_disable()

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The preempt_disable() invokes preempt_count_add() which saves the caller
in ->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_lock_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().

Steven asked for the get_parent_ip() -> get_lock_parent_ip() rename.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160226135456.GB18244@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Sebastian Andrzej Siewior 2016-02-26 14:54:56 +01:00 committed by Ingo Molnar
parent ff9a9b4c43
commit f904f58263
4 changed files with 16 additions and 16 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

12
include/linux/ftrace.h
View file

@ -713,6 +713,18 @@ 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);

2
include/linux/sched.h
View file

@ -182,8 +182,6 @@ extern void update_cpu_load_nohz(int active);
static inline void update_cpu_load_nohz(int active) { }
#endif
extern unsigned long get_parent_ip(unsigned long addr);
extern void dump_cpu_task(int cpu);
struct seq_file;

14
kernel/sched/core.c
View file

@ -2946,16 +2946,6 @@ 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))
@ -2977,7 +2967,7 @@ 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
@ -3004,7 +2994,7 @@ 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);

4
kernel/softirq.c
View file

@ -116,9 +116,9 @@ 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);