From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vincent Donnefort <vdonnefort@google.com>
Subject: [PATCH 2/2] tracing: Decrement the snapshot if the snapshot trigger fails to register
Date: Thu, 22 Feb 2024 20:33:25 -0500 [thread overview]
Message-ID: <20240223013344.729055907@goodmis.org> (raw)
In-Reply-To: 20240223013323.798805901@goodmis.org
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Running the ftrace selftests caused the ring buffer mapping test to fail.
Investigating, I found that the snapshot counter would be incremented
every time a snapshot trigger was added, even if that snapshot trigger
failed.
# cd /sys/kernel/tracing
# echo "snapshot" > events/sched/sched_process_fork/trigger
# echo "snapshot" > events/sched/sched_process_fork/trigger
-bash: echo: write error: File exists
That second one that fails increments the snapshot counter but doesn't
decrement it. It needs to be decremented when the snapshot fails.
Fixes: 16f7e48ffc53a ("tracing: Add snapshot refcount")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace_events_trigger.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 62e4f58b8671..4bec043c8690 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1491,7 +1491,10 @@ register_snapshot_trigger(char *glob,
if (ret < 0)
return ret;
- return register_trigger(glob, data, file);
+ ret = register_trigger(glob, data, file);
+ if (ret < 0)
+ tracing_disarm_snapshot(file->tr);
+ return ret;
}
static void unregister_snapshot_trigger(char *glob,
--
2.43.0
prev parent reply other threads:[~2024-02-23 1:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-23 1:33 [PATCH 0/2] tracing: Fix snapshot accounting Steven Rostedt
2024-02-23 1:33 ` [PATCH 1/2] tracing: Fix snapshot counter going between two tracers that use it Steven Rostedt
2024-02-23 1:33 ` Steven Rostedt [this message]
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