From c43ac4a5301986c015137bb89568979f9b3264ca Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 27 Nov 2018 09:36:37 -0500 Subject: tracing: Do not line wrap short line in function_graph_enter() Commit 588ca1786f2dd ("function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack") removed a parameter from the call ftrace_push_return_trace() that made it so that the entire call was under 80 characters, but it did not remove the line break. There's no reason to break that line up, so make it a single line. Link: http://lkml.kernel.org/r/20181122100322.GN2131@hirez.programming.kicks-ass.net Reported-by: Peter Zijlstra Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 086af4f5c3e8..0d235e44d08e 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -188,8 +188,7 @@ int function_graph_enter(unsigned long ret, unsigned long func, trace.func = func; trace.depth = ++current->curr_ret_depth; - if (ftrace_push_return_trace(ret, func, - frame_pointer, retp)) + if (ftrace_push_return_trace(ret, func, frame_pointer, retp)) goto out; /* Only trace if the calling function expects to */ -- cgit v1.2.3 From d864a3ca883095aa12575b84841ebd52b3d808fa Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 12 Nov 2018 15:21:22 -0500 Subject: fgraph: Create a fgraph.c file to store function graph infrastructure As the function graph infrastructure can be used by thing other than tracing, moving the code to its own file out of the trace_functions_graph.c code makes more sense. The fgraph.c file will only contain the infrastructure required to hook into functions and their return code. Reviewed-by: Joel Fernandes (Google) Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 220 ----------------------------------- 1 file changed, 220 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 0d235e44d08e..b846d82c2f95 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -16,33 +16,6 @@ #include "trace.h" #include "trace_output.h" -static bool kill_ftrace_graph; - -/** - * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called - * - * ftrace_graph_stop() is called when a severe error is detected in - * the function graph tracing. This function is called by the critical - * paths of function graph to keep those paths from doing any more harm. - */ -bool ftrace_graph_is_dead(void) -{ - return kill_ftrace_graph; -} - -/** - * ftrace_graph_stop - set to permanently disable function graph tracincg - * - * In case of an error int function graph tracing, this is called - * to try to keep function graph tracing from causing any more harm. - * Usually this is pretty severe and this is called to try to at least - * get a warning out to the user. - */ -void ftrace_graph_stop(void) -{ - kill_ftrace_graph = true; -} - /* When set, irq functions will be ignored */ static int ftrace_graph_skip_irqs; @@ -117,199 +90,6 @@ static void print_graph_duration(struct trace_array *tr, unsigned long long duration, struct trace_seq *s, u32 flags); -/* Add a function return address to the trace stack on thread info.*/ -static int -ftrace_push_return_trace(unsigned long ret, unsigned long func, - unsigned long frame_pointer, unsigned long *retp) -{ - unsigned long long calltime; - int index; - - if (unlikely(ftrace_graph_is_dead())) - return -EBUSY; - - if (!current->ret_stack) - return -EBUSY; - - /* - * We must make sure the ret_stack is tested before we read - * anything else. - */ - smp_rmb(); - - /* The return trace stack is full */ - if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) { - atomic_inc(¤t->trace_overrun); - return -EBUSY; - } - - /* - * The curr_ret_stack is an index to ftrace return stack of - * current task. Its value should be in [0, FTRACE_RETFUNC_ - * DEPTH) when the function graph tracer is used. To support - * filtering out specific functions, it makes the index - * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH) - * so when it sees a negative index the ftrace will ignore - * the record. And the index gets recovered when returning - * from the filtered function by adding the FTRACE_NOTRACE_ - * DEPTH and then it'll continue to record functions normally. - * - * The curr_ret_stack is initialized to -1 and get increased - * in this function. So it can be less than -1 only if it was - * filtered out via ftrace_graph_notrace_addr() which can be - * set from set_graph_notrace file in tracefs by user. - */ - if (current->curr_ret_stack < -1) - return -EBUSY; - - calltime = trace_clock_local(); - - index = ++current->curr_ret_stack; - if (ftrace_graph_notrace_addr(func)) - current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH; - barrier(); - current->ret_stack[index].ret = ret; - current->ret_stack[index].func = func; - current->ret_stack[index].calltime = calltime; -#ifdef HAVE_FUNCTION_GRAPH_FP_TEST - current->ret_stack[index].fp = frame_pointer; -#endif -#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR - current->ret_stack[index].retp = retp; -#endif - return 0; -} - -int function_graph_enter(unsigned long ret, unsigned long func, - unsigned long frame_pointer, unsigned long *retp) -{ - struct ftrace_graph_ent trace; - - trace.func = func; - trace.depth = ++current->curr_ret_depth; - - if (ftrace_push_return_trace(ret, func, frame_pointer, retp)) - goto out; - - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) - goto out_ret; - - return 0; - out_ret: - current->curr_ret_stack--; - out: - current->curr_ret_depth--; - return -EBUSY; -} - -/* Retrieve a function return address to the trace stack on thread info.*/ -static void -ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, - unsigned long frame_pointer) -{ - int index; - - index = current->curr_ret_stack; - - /* - * A negative index here means that it's just returned from a - * notrace'd function. Recover index to get an original - * return address. See ftrace_push_return_trace(). - * - * TODO: Need to check whether the stack gets corrupted. - */ - if (index < 0) - index += FTRACE_NOTRACE_DEPTH; - - if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) { - ftrace_graph_stop(); - WARN_ON(1); - /* Might as well panic, otherwise we have no where to go */ - *ret = (unsigned long)panic; - return; - } - -#ifdef HAVE_FUNCTION_GRAPH_FP_TEST - /* - * The arch may choose to record the frame pointer used - * and check it here to make sure that it is what we expect it - * to be. If gcc does not set the place holder of the return - * address in the frame pointer, and does a copy instead, then - * the function graph trace will fail. This test detects this - * case. - * - * Currently, x86_32 with optimize for size (-Os) makes the latest - * gcc do the above. - * - * Note, -mfentry does not use frame pointers, and this test - * is not needed if CC_USING_FENTRY is set. - */ - if (unlikely(current->ret_stack[index].fp != frame_pointer)) { - ftrace_graph_stop(); - WARN(1, "Bad frame pointer: expected %lx, received %lx\n" - " from func %ps return to %lx\n", - current->ret_stack[index].fp, - frame_pointer, - (void *)current->ret_stack[index].func, - current->ret_stack[index].ret); - *ret = (unsigned long)panic; - return; - } -#endif - - *ret = current->ret_stack[index].ret; - trace->func = current->ret_stack[index].func; - trace->calltime = current->ret_stack[index].calltime; - trace->overrun = atomic_read(¤t->trace_overrun); - trace->depth = current->curr_ret_depth--; - /* - * We still want to trace interrupts coming in if - * max_depth is set to 1. Make sure the decrement is - * seen before ftrace_graph_return. - */ - barrier(); -} - -/* - * Send the trace to the ring-buffer. - * @return the original return address. - */ -unsigned long ftrace_return_to_handler(unsigned long frame_pointer) -{ - struct ftrace_graph_ret trace; - unsigned long ret; - - ftrace_pop_return_trace(&trace, &ret, frame_pointer); - trace.rettime = trace_clock_local(); - ftrace_graph_return(&trace); - /* - * The ftrace_graph_return() may still access the current - * ret_stack structure, we need to make sure the update of - * curr_ret_stack is after that. - */ - barrier(); - current->curr_ret_stack--; - /* - * The curr_ret_stack can be less than -1 only if it was - * filtered out and it's about to return from the function. - * Recover the index and continue to trace normal functions. - */ - if (current->curr_ret_stack < -1) { - current->curr_ret_stack += FTRACE_NOTRACE_DEPTH; - return ret; - } - - if (unlikely(!ret)) { - ftrace_graph_stop(); - WARN_ON(1); - /* Might as well panic. What else to do? */ - ret = (unsigned long)panic; - } - - return ret; -} - /** * ftrace_graph_ret_addr - convert a potentially modified stack return address * to its original value -- cgit v1.2.3 From 9cd2992f2d6c8df54c5b937d5d1f8a23b684cc1d Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 14 Nov 2018 13:14:58 -0500 Subject: fgraph: Have set_graph_notrace only affect function_graph tracer In order to make the function graph infrastructure more generic, there can not be code specific for the function_graph tracer in the generic code. This includes the set_graph_notrace logic, that stops all graph calls when a function in the set_graph_notrace is hit. By using the trace_recursion mask, we can use a bit in the current task_struct to implement the notrace code, and move the logic out of fgraph.c and into trace_functions_graph.c and keeps it affecting only the tracer and not all call graph callbacks. Acked-by: Namhyung Kim Reviewed-by: Joel Fernandes (Google) Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index b846d82c2f95..ecf543df943b 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -188,6 +188,18 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) int cpu; int pc; + if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) + return 0; + + if (ftrace_graph_notrace_addr(trace->func)) { + trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT); + /* + * Need to return 1 to have the return called + * that will clear the NOTRACE bit. + */ + return 1; + } + if (!ftrace_trace_task(tr)) return 0; @@ -290,6 +302,11 @@ void trace_graph_return(struct ftrace_graph_ret *trace) ftrace_graph_addr_finish(trace); + if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) { + trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT); + return; + } + local_irq_save(flags); cpu = raw_smp_processor_id(); data = per_cpu_ptr(tr->trace_buffer.data, cpu); @@ -315,6 +332,11 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace) { ftrace_graph_addr_finish(trace); + if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) { + trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT); + return; + } + if (tracing_thresh && (trace->rettime - trace->calltime < tracing_thresh)) return; -- cgit v1.2.3 From 761efe8a94cfcd0a3dd90f2008411550f3520b63 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Sun, 18 Nov 2018 18:44:04 -0500 Subject: function_graph: Remove the use of FTRACE_NOTRACE_DEPTH The curr_ret_stack is no longer set to a negative value when a function is not to be traced by the function graph tracer. Remove the usage of FTRACE_NOTRACE_DEPTH, as it is no longer needed. Reviewed-by: Joel Fernandes (Google) Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index ecf543df943b..eaf9b1629956 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -115,9 +115,6 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, if (ret != (unsigned long)return_to_handler) return ret; - if (index < -1) - index += FTRACE_NOTRACE_DEPTH; - if (index < 0) return ret; @@ -675,10 +672,6 @@ print_graph_entry_leaf(struct trace_iterator *iter, cpu_data = per_cpu_ptr(data->cpu_data, cpu); - /* If a graph tracer ignored set_graph_notrace */ - if (call->depth < -1) - call->depth += FTRACE_NOTRACE_DEPTH; - /* * Comments display at + 1 to depth. Since * this is a leaf function, keep the comments @@ -721,10 +714,6 @@ print_graph_entry_nested(struct trace_iterator *iter, struct fgraph_cpu_data *cpu_data; int cpu = iter->cpu; - /* If a graph tracer ignored set_graph_notrace */ - if (call->depth < -1) - call->depth += FTRACE_NOTRACE_DEPTH; - cpu_data = per_cpu_ptr(data->cpu_data, cpu); cpu_data->depth = call->depth; -- cgit v1.2.3 From c8dd0f45874547e6e77bab03d71feb16c4cb98a8 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Fri, 23 Nov 2018 13:06:07 -0500 Subject: function_graph: Do not expose the graph_time option when profiler is not configured When the function profiler is not configured, the "graph_time" option is meaningless, as the function profiler is the only thing that makes use of it. Do not expose it if the profiler is not configured. Link: http://lkml.kernel.org/r/20181123061133.GA195223@google.com Reported-by: Joel Fernandes Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index eaf9b1629956..855c13c61e77 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -60,8 +60,12 @@ static struct tracer_opt trace_opts[] = { { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) }, /* Include sleep time (scheduled out) between entry and return */ { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) }, + +#ifdef CONFIG_FUNCTION_PROFILER /* Include time within nested functions */ { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) }, +#endif + { } /* Empty entry */ }; -- cgit v1.2.3 From 688f7089d8851b1a81106f0c0b9b29181b2f2dc8 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 15 Nov 2018 14:06:47 -0500 Subject: fgraph: Add new fgraph_ops structure to enable function graph hooks Currently the registering of function graph is to pass in a entry and return function. We need to have a way to associate those functions together where the entry can determine to run the return hook. Having a structure that contains both functions will facilitate the process of converting the code to be able to do such. This is similar to the way function hooks are enabled (it passes in ftrace_ops). Instead of passing in the functions to use, a single structure is passed in to the registering function. The unregister function is now passed in the fgraph_ops handle. When we allow more than one callback to the function graph hooks, this will let the system know which one to remove. Reviewed-by: Joel Fernandes (Google) Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 855c13c61e77..140b4b51ab34 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -345,17 +345,25 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace) trace_graph_return(trace); } +static struct fgraph_ops funcgraph_thresh_ops = { + .entryfunc = &trace_graph_entry, + .retfunc = &trace_graph_thresh_return, +}; + +static struct fgraph_ops funcgraph_ops = { + .entryfunc = &trace_graph_entry, + .retfunc = &trace_graph_return, +}; + static int graph_trace_init(struct trace_array *tr) { int ret; set_graph_array(tr); if (tracing_thresh) - ret = register_ftrace_graph(&trace_graph_thresh_return, - &trace_graph_entry); + ret = register_ftrace_graph(&funcgraph_thresh_ops); else - ret = register_ftrace_graph(&trace_graph_return, - &trace_graph_entry); + ret = register_ftrace_graph(&funcgraph_ops); if (ret) return ret; tracing_start_cmdline_record(); @@ -366,7 +374,10 @@ static int graph_trace_init(struct trace_array *tr) static void graph_trace_reset(struct trace_array *tr) { tracing_stop_cmdline_record(); - unregister_ftrace_graph(); + if (tracing_thresh) + unregister_ftrace_graph(&funcgraph_thresh_ops); + else + unregister_ftrace_graph(&funcgraph_ops); } static int graph_trace_update_thresh(struct trace_array *tr) -- cgit v1.2.3 From 76b42b63ed0d004961097d3a3cd979129d4afd26 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Sun, 18 Nov 2018 18:36:19 -0500 Subject: function_graph: Move ftrace_graph_ret_addr() to fgraph.c Move the function function_graph_ret_addr() to fgraph.c, as the management of the curr_ret_stack is going to change, and all the accesses to ret_stack needs to be done in fgraph.c. Reviewed-by: Joel Fernandes (Google) Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions_graph.c | 55 ------------------------------------ 1 file changed, 55 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 140b4b51ab34..c2af1560e856 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -94,61 +94,6 @@ static void print_graph_duration(struct trace_array *tr, unsigned long long duration, struct trace_seq *s, u32 flags); -/** - * ftrace_graph_ret_addr - convert a potentially modified stack return address - * to its original value - * - * This function can be called by stack unwinding code to convert a found stack - * return address ('ret') to its original value, in case the function graph - * tracer has modified it to be 'return_to_handler'. If the address hasn't - * been modified, the unchanged value of 'ret' is returned. - * - * 'idx' is a state variable which should be initialized by the caller to zero - * before the first call. - * - * 'retp' is a pointer to the return address on the stack. It's ignored if - * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined. - */ -#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR -unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, - unsigned long ret, unsigned long *retp) -{ - int index = task->curr_ret_stack; - int i; - - if (ret != (unsigned long)return_to_handler) - return ret; - - if (index < 0) - return ret; - - for (i = 0; i <= index; i++) - if (task->ret_stack[i].retp == retp) - return task->ret_stack[i].ret; - - return ret; -} -#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */ -unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, - unsigned long ret, unsigned long *retp) -{ - int task_idx; - - if (ret != (unsigned long)return_to_handler) - return ret; - - task_idx = task->curr_ret_stack; - - if (!task->ret_stack || task_idx < *idx) - return ret; - - task_idx -= *idx; - (*idx)++; - - return task->ret_stack[task_idx].ret; -} -#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */ - int __trace_graph_entry(struct trace_array *tr, struct ftrace_graph_ent *trace, unsigned long flags, -- cgit v1.2.3