[PATCH bpf v2] tools: bpftool: fix infinite loop in map create

[Alban Crequy]

From: Alban Crequy <alban@xxxxxxxxxx>

"bpftool map create" has an infinite loop on "while (argc)". The error
case is missing.

Symptoms: when forgetting to type the keyword 'type' in front of 'hash':
$ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
(infinite loop, taking all the CPU)
^C

After the patch:
$ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
Error: unknown arg hash

Fixes: 0b592b5a01be ("tools: bpftool: add map create command")
Signed-off-by: Alban Crequy <alban@xxxxxxxxxx>

---

Changes in v2:
- Explain the cause of the bug in commitmsg
- Add the "fixes" line in the commitmsg (Jakub's review)
- Rebase on the bpf tree

v1 was initially based on bpf-next and submitted on
https://marc.info/?l=linux-kernel&m=155310327709613&w=2
---
 tools/bpf/bpftool/map.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 05b029b934a6..1ccc38718458 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1151,6 +1151,9 @@ static int do_create(int argc, char **argv)
 				return -1;
 			}
 			NEXT_ARG();
+		} else {
+			p_err("unknown arg %s", *argv);
+			return -1;
 		}
 	}
 
-- 
2.20.1