From: Pietro Borrello borrello@diag.uniroma1.it
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...
Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe") Signed-off-by: Pietro Borrello borrello@diag.uniroma1.it Reviewed-by: Steven Rostedt (Google) rostedt@goodmis.org Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Acked-by: Mukesh Ojha quic_mojha@quicinc.com Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -302,7 +302,7 @@ 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)