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authorSteven Rostedt (Google) <rostedt@goodmis.org>2022-11-17 21:42:49 -0500
committerSteven Rostedt (Google) <rostedt@goodmis.org>2022-11-20 14:05:50 -0500
commit94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26 (patch)
tree233feca1ebea1094b096d6a1378047cd37eaece7 /kernel
parent067df9e0ad48a97382ab2179bbe773a13a846028 (diff)
tracing: Fix race where eprobes can be called before the event
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_eprobe.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 5dd0617e5df6..9cda9a38422c 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -563,6 +563,9 @@ 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);
}