From: Pietro Borrello <borrello@xxxxxxxxxxxxxxxx> commit 81d0fa4cb4fc0e1a49c2b22f92c43d9fe972ebcf upstream. All callers of trace_probe_primary_from_call() check the return value to be non NULL. However, the function returns list_first_entry(&tpe->probes, ...) which can never be NULL. Additionally, it does not check for the list being possibly empty, possibly causing a type confusion on empty lists. Use list_first_entry_or_null() which solves both problems. Link: https://lore.kernel.org/linux-trace-kernel/20230128-list-entry-null-check-v1-1-8bde6a3da2ef@xxxxxxxxxxxxxxxx/ Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe") Signed-off-by: Pietro Borrello <borrello@xxxxxxxxxxxxxxxx> Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Acked-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/trace_probe.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -301,7 +301,7 @@ trace_probe_primary_from_call(struct tra { struct trace_probe_event *tpe = trace_probe_event_from_call(call); - return list_first_entry(&tpe->probes, struct trace_probe, list); + return list_first_entry_or_null(&tpe->probes, struct trace_probe, list); } static inline struct list_head *trace_probe_probe_list(struct trace_probe *tp)
