On Fri, Sep 15, 2023 at 10:12:34AM +0300, Dan Carpenter wrote:
> Hello Jiri Olsa,
>
> The patch b733eeade420: "bpf: Add pid filter support for uprobe_multi
> link" from Aug 9, 2023 (linux-next), leads to the following Smatch
> static checker warning:
>
> kernel/trace/bpf_trace.c:3227 bpf_uprobe_multi_link_attach()
> warn: missing error code here? 'get_pid_task()' failed. 'err' = '0'
>
> kernel/trace/bpf_trace.c
> 3217 err = -EBADF;
> 3218 goto error_path_put;
> 3219 }
> 3220
> 3221 pid = attr->link_create.uprobe_multi.pid;
> 3222 if (pid) {
> 3223 rcu_read_lock();
> 3224 task = get_pid_task(find_vpid(pid), PIDTYPE_PID);
> 3225 rcu_read_unlock();
> 3226 if (!task)
> --> 3227 goto error_path_put;
>
> Should this have an error code?
yes, it should.. I'll send the fix below
thanks,
jirka
---
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index c1c1af63ced2..868008f56fec 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3223,8 +3223,10 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
rcu_read_lock();
task = get_pid_task(find_vpid(pid), PIDTYPE_PID);
rcu_read_unlock();
- if (!task)
+ if (!task) {
+ err = -ESRCH;
goto error_path_put;
+ }
}
err = -ENOMEM;
