summaryrefslogtreecommitdiffstats
path: root/kernel/trace/trace_functions.c
diff options
context:
space:
mode:
authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-04-30 19:00:46 -0400
committerSteven Rostedt <rostedt@goodmis.org>2013-06-11 18:38:48 -0400
commit90e3c03c3a09a7b176b3fe59d78f5d9755ac8e37 (patch)
treea37db37999a01fb1f425a19f5a9615faf1059b73 /kernel/trace/trace_functions.c
parentad71d889b88055e61e3970a6744a271a51a94f42 (diff)
downloadblackbird-op-linux-90e3c03c3a09a7b176b3fe59d78f5d9755ac8e37.tar.gz
blackbird-op-linux-90e3c03c3a09a7b176b3fe59d78f5d9755ac8e37.zip
tracing: Add function probe to trigger a ftrace dump of current CPU trace
Add the "cpudump" command to have the current CPU ftrace buffer dumped to console if a function is hit. This is useful when debugging a tripple fault, where you have an idea of a function that is called just before the tripple fault occurs, and can tell ftrace to dump its content out to the console before it continues. This differs from the "dump" command as it only dumps the content of the ring buffer for the currently executing CPU, and does not show the contents of the other CPUs. Format is: <function>:cpudump echo 'bad_address:cpudump' > /debug/tracing/set_ftrace_filter To remove this: echo '!bad_address:cpudump' > /debug/tracing/set_ftrace_filter Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_functions.c')
-rw-r--r--kernel/trace/trace_functions.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index d7c8719734b8..b863f93b30f3 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -297,6 +297,14 @@ ftrace_dump_probe(unsigned long ip, unsigned long parent_ip, void **data)
ftrace_dump(DUMP_ALL);
}
+/* Only dump the current CPU buffer. */
+static void
+ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip, void **data)
+{
+ if (update_count(data))
+ ftrace_dump(DUMP_ORIG);
+}
+
static int
ftrace_probe_print(const char *name, struct seq_file *m,
unsigned long ip, void *data)
@@ -341,6 +349,13 @@ ftrace_dump_print(struct seq_file *m, unsigned long ip,
return ftrace_probe_print("dump", m, ip, data);
}
+static int
+ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
+ struct ftrace_probe_ops *ops, void *data)
+{
+ return ftrace_probe_print("cpudump", m, ip, data);
+}
+
static struct ftrace_probe_ops traceon_count_probe_ops = {
.func = ftrace_traceon_count,
.print = ftrace_traceon_print,
@@ -361,6 +376,11 @@ static struct ftrace_probe_ops dump_probe_ops = {
.print = ftrace_dump_print,
};
+static struct ftrace_probe_ops cpudump_probe_ops = {
+ .func = ftrace_cpudump_probe,
+ .print = ftrace_cpudump_print,
+};
+
static struct ftrace_probe_ops traceon_probe_ops = {
.func = ftrace_traceon,
.print = ftrace_traceon_print,
@@ -457,6 +477,19 @@ ftrace_dump_callback(struct ftrace_hash *hash,
"1", enable);
}
+static int
+ftrace_cpudump_callback(struct ftrace_hash *hash,
+ char *glob, char *cmd, char *param, int enable)
+{
+ struct ftrace_probe_ops *ops;
+
+ ops = &cpudump_probe_ops;
+
+ /* Only dump once. */
+ return ftrace_trace_probe_callback(ops, hash, glob, cmd,
+ "1", enable);
+}
+
static struct ftrace_func_command ftrace_traceon_cmd = {
.name = "traceon",
.func = ftrace_trace_onoff_callback,
@@ -477,6 +510,11 @@ static struct ftrace_func_command ftrace_dump_cmd = {
.func = ftrace_dump_callback,
};
+static struct ftrace_func_command ftrace_cpudump_cmd = {
+ .name = "cpudump",
+ .func = ftrace_cpudump_callback,
+};
+
static int __init init_func_cmd_traceon(void)
{
int ret;
@@ -497,8 +535,14 @@ static int __init init_func_cmd_traceon(void)
if (ret)
goto out_free_stacktrace;
+ ret = register_ftrace_command(&ftrace_cpudump_cmd);
+ if (ret)
+ goto out_free_dump;
+
return 0;
+ out_free_dump:
+ unregister_ftrace_command(&ftrace_dump_cmd);
out_free_stacktrace:
unregister_ftrace_command(&ftrace_stacktrace_cmd);
out_free_traceon:
OpenPOWER on IntegriCloud