[PATCH] tracing: uprobes: Fix incorrect __free function that frees an error value in __trace_uprobe_create()

[Ella Ma <alansnape3058@gmail.com>]

Before applying the __free annotation, the original version goes to
label `fail_address_parse`, and does not call function
`free_trace_uprobe` on pointer `tu`. However, after the change, the
function will be called whenever the function returns. This makes the
error value returned by `alloc_trace_uprobe` get freed.

This patch fixes this issue by adding the check for error value in the
__free function definition.

Found by Clang Static Analyzer (my own development fork
https://github.com/Snape3058/llvm-patch-revision/tree/cleanup).

	warning: Argument to 'kfree()' is a constant address
	(18446744073709551604), which is not memory allocated by
	'malloc()' [unix.Malloc]

Fixes: 8b658df20658 ("tracing: uprobes: Cleanup __trace_uprobe_create() with __free()")
Signed-off-by: Ella Ma <alansnape3058@gmail.com>
---
 kernel/trace/trace_uprobe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index c274346853d1..ccbdc96e5578 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -533,7 +533,7 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 	return ret;
 }
 
-DEFINE_FREE(free_trace_uprobe, struct trace_uprobe *, if (_T) free_trace_uprobe(_T))
+DEFINE_FREE(free_trace_uprobe, struct trace_uprobe *, if (!IS_ERR_OR_NULL(_T)) free_trace_uprobe(_T))
 
 /*
  * Argument syntax:
-- 
2.34.1