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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2021-08-16 23:42:57 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-08-18 18:13:47 -0400
commit1d18538e6a09265003a0a94ca779d7a6127cb76c (patch)
tree79c71bb9a4c4ed5a3848bdbb155b6b1dfe8a08a0 /kernel/trace/trace_kprobe.c
parent8b0e6c744fef6462382041b30878c91f15069fc6 (diff)
downloadlinux-1d18538e6a09265003a0a94ca779d7a6127cb76c.tar.gz
tracing: Have dynamic events have a ref counter
As dynamic events are not created by modules, if something is attached to
one, calling "try_module_get()" on its "mod" field, is not going to keep
the dynamic event from going away.

Since dynamic events do not need the "mod" pointer of the event structure,
make a union out of it in order to save memory (there's one structure for
each of the thousand+ events in the kernel), and have any event with the
DYNAMIC flag set to use a ref counter instead.

Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/
Link: https://lkml.kernel.org/r/20210817035027.174869074@goodmis.org

Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
-rw-r--r--kernel/trace/trace_kprobe.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index bfef43bfce37..82c3b86013b2 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -543,6 +543,10 @@ static int unregister_trace_kprobe(struct trace_kprobe *tk)
 	if (trace_probe_is_enabled(&tk->tp))
 		return -EBUSY;
 
+	/* If there's a reference to the dynamic event */
+	if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
+		return -EBUSY;
+
 	/* Will fail if probe is being used by ftrace or perf */
 	if (unregister_kprobe_event(tk))
 		return -EBUSY;