From d9e540762f5cdd89f24e518ad1fd31142d0b9726 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 1 Nov 2008 19:57:37 +0100 Subject: ftrace: ftrace_dump_on_oops=[tracer] Impact: add new (optional) debug boot option In order to facilitate early boot trouble, allow one to specify a tracer on the kernel boot line. Signed-off-by: Peter Zijlstra Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 58 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bdb1df00fb10..482583eb8001 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -79,6 +79,15 @@ static int tracing_disabled = 1; */ int ftrace_dump_on_oops; +static int tracing_set_tracer(char *buf); + +static int __init set_ftrace(char *str) +{ + tracing_set_tracer(str); + return 1; +} +__setup("ftrace", set_ftrace); + static int __init set_ftrace_dump_on_oops(char *str) { ftrace_dump_on_oops = 1; @@ -2394,29 +2403,11 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf, return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } -static ssize_t -tracing_set_trace_write(struct file *filp, const char __user *ubuf, - size_t cnt, loff_t *ppos) +static int tracing_set_tracer(char *buf) { struct trace_array *tr = &global_trace; struct tracer *t; - char buf[max_tracer_type_len+1]; - int i; - size_t ret; - - ret = cnt; - - if (cnt > max_tracer_type_len) - cnt = max_tracer_type_len; - - if (copy_from_user(&buf, ubuf, cnt)) - return -EFAULT; - - buf[cnt] = 0; - - /* strip ending whitespace. */ - for (i = cnt - 1; i > 0 && isspace(buf[i]); i--) - buf[i] = 0; + int ret = 0; mutex_lock(&trace_types_lock); for (t = trace_types; t; t = t->next) { @@ -2440,6 +2431,33 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf, out: mutex_unlock(&trace_types_lock); + return ret; +} + +static ssize_t +tracing_set_trace_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[max_tracer_type_len+1]; + int i; + size_t ret; + + if (cnt > max_tracer_type_len) + cnt = max_tracer_type_len; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + /* strip ending whitespace. */ + for (i = cnt - 1; i > 0 && isspace(buf[i]); i--) + buf[i] = 0; + + ret = tracing_set_tracer(buf); + if (!ret) + ret = cnt; + if (ret > 0) filp->f_pos += ret; -- cgit v1.2.3-59-g8ed1b