diff options
| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-11-17 21:42:49 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-26 09:27:41 +0100 |
| commit | 73f5191467ffe3af82f27fe0ea6a8c2fac724d3f (patch) | |
| tree | c7ae57680502851f4b204085b7e73969efe42579 | |
| parent | a5bfa53e5036b3e7a80be902dd3719a930accabd (diff) | |
tracing: Fix race where eprobes can be called before the event
commit 94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26 upstream.
The flag that tells the event to call its triggers after reading the event
is set for eprobes after the eprobe is enabled. This leads to a race where
the eprobe may be triggered at the beginning of the event where the record
information is NULL. The eprobe then dereferences the NULL record causing
a NULL kernel pointer bug.
Test for a NULL record to keep this from happening.
Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20221117214249.2addbe10@gandalf.local.home
Cc: Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/trace/trace_eprobe.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 860f5fb9514d..3b055aaee89a 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -560,6 +560,9 @@ static void eprobe_trigger_func(struct event_trigger_data *data, { struct eprobe_data *edata = data->private_data; + if (unlikely(!rec)) + return; + __eprobe_trace_func(edata, rec); } |