From d2d45c7a03a2b1a14159cbb665e9dd60991a7d4f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 19 Dec 2011 14:44:09 -0500 Subject: tracing: Have stack_tracer use a separate list of functions The stack_tracer is used to look at every function and check if the current stack is bigger than the last recorded max stack size. When a new max is found, then it saves that stack off. Currently the stack tracer is limited by the global_ops of the function tracer. As the stack tracer has nothing to do with the ftrace function tracer, except that it uses it as its internal engine, the stack tracer should have its own list. A new file is added to the tracing debugfs directory called: stack_trace_filter that can be used to select which functions you want to check the stack on. Signed-off-by: Steven Rostedt --- kernel/trace/trace_stack.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace_stack.c') diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 77575b386d97..0398b7c7afd6 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -133,7 +133,6 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip) static struct ftrace_ops trace_ops __read_mostly = { .func = stack_trace_call, - .flags = FTRACE_OPS_FL_GLOBAL, }; static ssize_t @@ -311,6 +310,21 @@ static const struct file_operations stack_trace_fops = { .release = seq_release, }; +static int +stack_trace_filter_open(struct inode *inode, struct file *file) +{ + return ftrace_regex_open(&trace_ops, FTRACE_ITER_FILTER, + inode, file); +} + +static const struct file_operations stack_trace_filter_fops = { + .open = stack_trace_filter_open, + .read = seq_read, + .write = ftrace_filter_write, + .llseek = ftrace_regex_lseek, + .release = ftrace_regex_release, +}; + int stack_trace_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, @@ -358,6 +372,9 @@ static __init int stack_trace_init(void) trace_create_file("stack_trace", 0444, d_tracer, NULL, &stack_trace_fops); + trace_create_file("stack_trace_filter", 0444, d_tracer, + NULL, &stack_trace_filter_fops); + if (stack_tracer_enabled) register_ftrace_function(&trace_ops); -- cgit v1.2.3 From 762e1207889b3451c50d365b741af6f9ce958886 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 19 Dec 2011 22:01:00 -0500 Subject: tracing: Have stack tracing set filtered functions at boot Add stacktrace_filter= to the kernel command line that lets the user pick specific functions to check the stack on. Signed-off-by: Steven Rostedt --- Documentation/kernel-parameters.txt | 8 ++++++++ kernel/trace/trace_stack.c | 11 +++++++++++ 2 files changed, 19 insertions(+) (limited to 'kernel/trace/trace_stack.c') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index fd5c913c33c1..fde2ae06539a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2435,6 +2435,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. stacktrace [FTRACE] Enabled the stack tracer on boot up. + stacktrace_filter=[function-list] + [FTRACE] Limit the functions that the stack tracer + will trace at boot up. function-list is a comma separated + list of functions. This list can be changed at run + time by the stack_trace_filter file in the debugfs + tracing directory. Note, this enables stack tracing + and the stacktrace above is not needed. + sti= [PARISC,HW] Format: Set the STI (builtin display/keyboard on the HP-PARISC diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 0398b7c7afd6..d4545f49242e 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -13,6 +13,9 @@ #include #include #include + +#include + #include "trace.h" #define STACK_TRACE_ENTRIES 500 @@ -352,8 +355,13 @@ stack_trace_sysctl(struct ctl_table *table, int write, return ret; } +static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata; + static __init int enable_stacktrace(char *str) { + if (strncmp(str, "_filter=", 8) == 0) + strncpy(stack_trace_filter_buf, str+8, COMMAND_LINE_SIZE); + stack_tracer_enabled = 1; last_stack_tracer_enabled = 1; return 1; @@ -375,6 +383,9 @@ static __init int stack_trace_init(void) trace_create_file("stack_trace_filter", 0444, d_tracer, NULL, &stack_trace_filter_fops); + if (stack_trace_filter_buf[0]) + ftrace_set_early_filter(&trace_ops, stack_trace_filter_buf, 1); + if (stack_tracer_enabled) register_ftrace_function(&trace_ops); -- cgit v1.2.3