3.12.54-rt74-rc1 stable review patch. If anyone has any objections, please let me know.
------------------ From: Sebastian Andrzej Siewior <[email protected]> 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 <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- 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 e68db4d534cb..9b7b9341f886 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -627,6 +627,18 @@ 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 3ce814c4ef42..4006703785b2 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -113,8 +113,6 @@ 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 7e56dc293669..c66db09aaf12 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2279,16 +2279,6 @@ 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)) @@ -2310,7 +2300,7 @@ void __kprobes add_preempt_count(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 @@ -2336,7 +2326,7 @@ void __kprobes sub_preempt_count(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() -= val; } EXPORT_SYMBOL(sub_preempt_count); diff --git a/kernel/softirq.c b/kernel/softirq.c index 7c8e36bf9e2a..315b048423af 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -277,7 +277,7 @@ static void __local_bh_disable(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()); } #else /* !CONFIG_TRACE_IRQFLAGS */ static inline void __local_bh_disable(unsigned long ip, unsigned int cnt) -- 2.7.0
