[PATCH v2] samples: bpf: fix: seg fault with NULL pointer arg

[Daniel T. Lee]

When NULL pointer accidentally passed to write_kprobe_events,
due to strlen(NULL), segmentation fault happens.
Changed code returns -1 to deal with this situation.

Bug issued with Smatch, static analysis.

Signed-off-by: Daniel T. Lee <danieltim...@gmail.com>
---
 samples/bpf/bpf_load.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 434ea34a5954..eae7b635343d 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -58,7 +58,9 @@ static int write_kprobe_events(const char *val)
 {
        int fd, ret, flags;
 
-       if ((val != NULL) && (val[0] == '\0'))
+       if (val == NULL)
+               return -1;
+       else if (val[0] == '\0')
                flags = O_WRONLY | O_TRUNC;
        else
                flags = O_WRONLY | O_APPEND;
-- 
2.17.1