bpf: Clear the probe_addr for uprobe

[ Upstream commit 5125e757e62f6c1d5478db4c2b61a744060ddf3f ]

To avoid returning uninitialized or random values when querying the file
descriptor (fd) and accessing probe_addr, it is necessary to clear the
variable prior to its use.

Fixes: 41bdc4b40e ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230709025630.3735-6-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

kernel/trace/bpf_trace.c

@@ -2174,7 +2174,7 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
 #ifdef CONFIG_UPROBE_EVENTS
 		if (flags & TRACE_EVENT_FL_UPROBE)
 			err = bpf_get_uprobe_info(event, fd_type, buf,
-						  probe_offset,
+						  probe_offset, probe_addr,
 						  event->attr.type == PERF_TYPE_TRACEPOINT);
 #endif
 	}

kernel/trace/trace_uprobe.c

@@ -1422,7 +1422,7 @@ static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
 
 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
 			const char **filename, u64 *probe_offset,
-			bool perf_type_tracepoint)
+			u64 *probe_addr, bool perf_type_tracepoint)
 {
 	const char *pevent = trace_event_name(event->tp_event);
 	const char *group = event->tp_event->class->system;
@@ -1439,6 +1439,7 @@ int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
 				    : BPF_FD_TYPE_UPROBE;
 	*filename = tu->filename;
 	*probe_offset = tu->offset;
+	*probe_addr = 0;
 	return 0;
 }
 #endif	/* CONFIG_PERF_EVENTS */