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authorOleg Nesterov <oleg@redhat.com>2013-07-29 19:50:33 +0200
committerSteven Rostedt <rostedt@goodmis.org>2013-07-31 13:12:48 -0400
commit2816c551c796ec14620325b2c9ed75b9979d3125 (patch)
treec4bc262514de5ef265001411bcdf7ad65916eae9 /include
parent776164c1faac4966ab14418bb0922e1820da1d19 (diff)
tracing: trace_remove_event_call() should fail if call/file is in use
Change trace_remove_event_call(call) to return the error if this call is active. This is what the callers assume but can't verify outside of the tracing locks. Both trace_kprobe.c/trace_uprobe.c need the additional changes, unregister_trace_probe() should abort if trace_remove_event_call() fails. The caller is going to free this call/file so we must ensure that nobody can use them after trace_remove_event_call() succeeds. debugfs should be fine after the previous changes and event_remove() does TRACE_REG_UNREGISTER, but still there are 2 reasons why we need the additional checks: - There could be a perf_event(s) attached to this tp_event, so the patch checks ->perf_refcount. - TRACE_REG_UNREGISTER can be suppressed by FTRACE_EVENT_FL_SOFT_MODE, so we simply check FTRACE_EVENT_FL_ENABLED protected by event_mutex. Link: http://lkml.kernel.org/r/20130729175033.GB26284@redhat.com Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/ftrace_event.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 4372658c73ae..f98ab063e95e 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -332,7 +332,7 @@ extern int trace_define_field(struct ftrace_event_call *call, const char *type,
const char *name, int offset, int size,
int is_signed, int filter_type);
extern int trace_add_event_call(struct ftrace_event_call *call);
-extern void trace_remove_event_call(struct ftrace_event_call *call);
+extern int trace_remove_event_call(struct ftrace_event_call *call);
#define is_signed_type(type) (((type)(-1)) < (type)1)