From 1a41442864e35bff859582fe9c5d051d0b1040ba Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 8 Dec 2016 19:28:28 -0500 Subject: [PATCH] tracing/fgraph: Have wakeup and irqsoff tracers ignore graph functions too Currently both the wakeup and irqsoff traces do not handle set_graph_notrace well. The ftrace infrastructure will ignore the return paths of all functions leaving them hanging without an end: # echo '*spin*' > set_graph_notrace # cat trace [...] _raw_spin_lock() { preempt_count_add() { do_raw_spin_lock() { update_rq_clock(); Where the '*spin*' functions should have looked like this: _raw_spin_lock() { preempt_count_add(); do_raw_spin_lock(); } update_rq_clock(); Instead, have the wakeup and irqsoff tracers ignore the functions that are set by the set_graph_notrace like the function_graph tracer does. Move the logic in the function_graph tracer into a header to allow wakeup and irqsoff tracers to use it as well. Cc: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 11 +++++++++++ kernel/trace/trace_functions_graph.c | 14 +++++++------- kernel/trace/trace_irqsoff.c | 12 ++++++++++++ kernel/trace/trace_sched_wakeup.c | 12 ++++++++++++ 4 files changed, 42 insertions(+), 7 deletions(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 37602e722336..c2234494f40c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -846,6 +846,17 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr) return 0; } #endif /* CONFIG_DYNAMIC_FTRACE */ + +extern unsigned int fgraph_max_depth; + +static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace) +{ + /* trace it when it is-nested-in or is a function enabled. */ + return !(trace->depth || ftrace_graph_addr(trace->func)) || + (trace->depth < 0) || + (fgraph_max_depth && trace->depth >= fgraph_max_depth); +} + #else /* CONFIG_FUNCTION_GRAPH_TRACER */ static inline enum print_line_t print_graph_function_flags(struct trace_iterator *iter, u32 flags) diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 566f7327c3aa..d56123cdcc89 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -65,7 +65,7 @@ struct fgraph_data { #define TRACE_GRAPH_INDENT 2 -static unsigned int max_depth; +unsigned int fgraph_max_depth; static struct tracer_opt trace_opts[] = { /* Display overruns? (for self-debug purpose) */ @@ -384,10 +384,10 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) if (!ftrace_trace_task(tr)) return 0; - /* trace it when it is-nested-in or is a function enabled. */ - if ((!(trace->depth || ftrace_graph_addr(trace->func)) || - ftrace_graph_ignore_irqs()) || (trace->depth < 0) || - (max_depth && trace->depth >= max_depth)) + if (ftrace_graph_ignore_func(trace)) + return 0; + + if (ftrace_graph_ignore_irqs()) return 0; /* @@ -1500,7 +1500,7 @@ graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt, if (ret) return ret; - max_depth = val; + fgraph_max_depth = val; *ppos += cnt; @@ -1514,7 +1514,7 @@ graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt, char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/ int n; - n = sprintf(buf, "%d\n", max_depth); + n = sprintf(buf, "%d\n", fgraph_max_depth); return simple_read_from_buffer(ubuf, cnt, ppos, buf, n); } diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 03cdff84d026..86654d7e1afe 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -175,6 +175,18 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace) int ret; int pc; + if (ftrace_graph_ignore_func(trace)) + return 0; + /* + * Do not trace a function if it's filtered by set_graph_notrace. + * Make the index of ret stack negative to indicate that it should + * ignore further functions. But it needs its own ret stack entry + * to recover the original index in order to continue tracing after + * returning from the function. + */ + if (ftrace_graph_notrace_addr(trace->func)) + return 1; + if (!func_prolog_dec(tr, &data, &flags)) return 0; diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 1bf2324dc682..5d0bb025bb21 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -239,6 +239,18 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace) unsigned long flags; int pc, ret = 0; + if (ftrace_graph_ignore_func(trace)) + return 0; + /* + * Do not trace a function if it's filtered by set_graph_notrace. + * Make the index of ret stack negative to indicate that it should + * ignore further functions. But it needs its own ret stack entry + * to recover the original index in order to continue tracing after + * returning from the function. + */ + if (ftrace_graph_notrace_addr(trace->func)) + return 1; + if (!func_prolog_preempt_disable(tr, &data, &pc)) return 0; -- 2.20.1