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| author | Steven Rostedt <srostedt@redhat.com> | 2011-12-19 22:01:00 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2011-12-21 07:26:49 -0500 |
| commit | 762e1207889b3451c50d365b741af6f9ce958886 (patch) | |
| tree | dcb1f4eacbddfa342181a29a97eb9b994922b009 | |
| parent | 2a85a37f168d2b4d74d493b578af4dc9032be92e (diff) | |
| download | linux-next-762e1207889b3451c50d365b741af6f9ce958886.tar.gz | |
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 <rostedt@goodmis.org>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 8 | ||||
| -rw-r--r-- | kernel/trace/trace_stack.c | 11 |
2 files changed, 19 insertions, 0 deletions
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: <num> 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 <linux/sysctl.h> #include <linux/init.h> #include <linux/fs.h> + +#include <asm/setup.h> + #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); |