summaryrefslogtreecommitdiffstats
path: root/kernel/trace/trace_events.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-11 17:04:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-11 17:04:59 -0700
commit26b840ae5d5140fe7b2226098826c449e63de072 (patch)
tree0f4a6f1575a7f0e49f63da7920258e1e89359036 /kernel/trace/trace_events.c
parent607eeb0b836aa24a6972a460a213c4f87902d403 (diff)
parentb8820084f2130b3dcfb09c78ac16cdd2194a345b (diff)
Merge tag 'trace-fixes-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing/kprobes update from Steven Rostedt: "The majority of these changes are from Masami Hiramatsu bringing kprobes up to par with the latest changes to ftrace (multi buffering and the new function probes). He also discovered and fixed some bugs in doing so. When pulling in his patches, I also found a few minor bugs as well and fixed them. This also includes a compile fix for some archs that select the ring buffer but not tracing. I based this off of the last patch you took from me that fixed the merge conflict error, as that was the commit that had all the changes I needed for this set of changes." * tag 'trace-fixes-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing/kprobes: Support soft-mode disabling tracing/kprobes: Support ftrace_event_file base multibuffer tracing/kprobes: Pass trace_probe directly from dispatcher tracing/kprobes: Increment probe hit-count even if it is used by perf tracing/kprobes: Use bool for retprobe checker ftrace: Fix function probe when more than one probe is added ftrace: Fix the output of enabled_functions debug file ftrace: Fix locking in register_ftrace_function_probe() tracing: Add helper function trace_create_new_event() to remove duplicate code tracing: Modify soft-mode only if there's no other referrer tracing: Indicate enabled soft-mode in enable file tracing/kprobes: Fix to increment return event probe hit-count ftrace: Cleanup regex_lock and ftrace_lock around hash updating ftrace, kprobes: Fix a deadlock on ftrace_regex_lock ftrace: Have ftrace_regex_write() return either read or error tracing: Return error if register_ftrace_function_probe() fails for event_enable_func() tracing: Don't succeed if event_enable_func did not register anything ring-buffer: Select IRQ_WORK
Diffstat (limited to 'kernel/trace/trace_events.c')
-rw-r--r--kernel/trace/trace_events.c54
1 files changed, 41 insertions, 13 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53582e982e5..7a0cf68027c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -251,7 +251,8 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
switch (enable) {
case 0:
/*
- * When soft_disable is set and enable is cleared, we want
+ * When soft_disable is set and enable is cleared, the sm_ref
+ * reference counter is decremented. If it reaches 0, we want
* to clear the SOFT_DISABLED flag but leave the event in the
* state that it was. That is, if the event was enabled and
* SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
@@ -263,6 +264,8 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
* "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
*/
if (soft_disable) {
+ if (atomic_dec_return(&file->sm_ref) > 0)
+ break;
disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
} else
@@ -291,8 +294,11 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
*/
if (!soft_disable)
clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
- else
+ else {
+ if (atomic_inc_return(&file->sm_ref) > 1)
+ break;
set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
+ }
if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
@@ -623,6 +629,8 @@ event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
if (file->flags & FTRACE_EVENT_FL_ENABLED) {
if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED)
buf = "0*\n";
+ else if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
+ buf = "1*\n";
else
buf = "1\n";
} else
@@ -1521,6 +1529,24 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
return 0;
}
+static struct ftrace_event_file *
+trace_create_new_event(struct ftrace_event_call *call,
+ struct trace_array *tr)
+{
+ struct ftrace_event_file *file;
+
+ file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ if (!file)
+ return NULL;
+
+ file->event_call = call;
+ file->tr = tr;
+ atomic_set(&file->sm_ref, 0);
+ list_add(&file->list, &tr->events);
+
+ return file;
+}
+
/* Add an event to a trace directory */
static int
__trace_add_new_event(struct ftrace_event_call *call,
@@ -1532,14 +1558,10 @@ __trace_add_new_event(struct ftrace_event_call *call,
{
struct ftrace_event_file *file;
- file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ file = trace_create_new_event(call, tr);
if (!file)
return -ENOMEM;
- file->event_call = call;
- file->tr = tr;
- list_add(&file->list, &tr->events);
-
return event_create_dir(tr->event_dir, file, id, enable, filter, format);
}
@@ -1554,14 +1576,10 @@ __trace_early_add_new_event(struct ftrace_event_call *call,
{
struct ftrace_event_file *file;
- file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ file = trace_create_new_event(call, tr);
if (!file)
return -ENOMEM;
- file->event_call = call;
- file->tr = tr;
- list_add(&file->list, &tr->events);
-
return 0;
}
@@ -2061,8 +2079,18 @@ event_enable_func(struct ftrace_hash *hash,
if (ret < 0)
goto out_put;
ret = register_ftrace_function_probe(glob, ops, data);
- if (!ret)
+ /*
+ * The above returns on success the # of functions enabled,
+ * but if it didn't find any functions it returns zero.
+ * Consider no functions a failure too.
+ */
+ if (!ret) {
+ ret = -ENOENT;
+ goto out_disable;
+ } else if (ret < 0)
goto out_disable;
+ /* Just return zero, not the number of enabled functions */
+ ret = 0;
out:
mutex_unlock(&event_mutex);
return ret;