[PATCH AUTOSEL 5.0 069/262] tools/bpf: selftests: add map lookup to test_map_in_map bpf prog

Sasha Levin
2019-03-27T19:28:58Z

From: Yonghong Song <yhs@fb.com>

[ Upstream commit 9eca5083757b679b37f210092c871916c2c222d0 ]

The bpf_map_lookup_elem is added in the bpf program.
Without previous patch, the test change will trigger the
following error:
$ ./test_maps
...
; value_p = bpf_map_lookup_elem(map, &key);
20: (bf) r1 = r7
21: (bf) r2 = r8
22: (85) call bpf_map_lookup_elem#1
; if (!value_p || *value_p != 123)
23: (15) if r0 == 0x0 goto pc+16
R0=map_value(id=2,off=0,ks=4,vs=4,imm=0) R6=inv1 R7=map_ptr(id=0,off=0,ks=4,vs=4,imm=0)
R8=fp-8,call_-1 R10=fp0,call_-1 fp-8=mmmmmmmm
; if (!value_p || *value_p != 123)
24: (61) r1 = *(u32 *)(r0 +0)
R0=map_value(id=2,off=0,ks=4,vs=4,imm=0) R6=inv1 R7=map_ptr(id=0,off=0,ks=4,vs=4,imm=0)
R8=fp-8,call_-1 R10=fp0,call_-1 fp-8=mmmmmmmm
bpf_spin_lock cannot be accessed directly by load/store

With the kernel fix in the previous commit, the error goes away.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/bpf/test_map_in_map.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/bpf/test_map_in_map.c b/tools/testing/selftests/bpf/test_map_in_map.c
index ce923e67e08e..2985f262846e 100644
--- a/tools/testing/selftests/bpf/test_map_in_map.c
+++ b/tools/testing/selftests/bpf/test_map_in_map.c
@@ -27,6 +27,7 @@ SEC("xdp_mimtest")
int xdp_mimtest0(struct xdp_md *ctx)
{
int value = 123;
+ int *value_p;
int key = 0;
void *map;

@@ -35,6 +36,9 @@ int xdp_mimtest0(struct xdp_md *ctx)
return XDP_DROP;

bpf_map_update_elem(map, &key, &value, 0);
+ value_p = bpf_map_lookup_elem(map, &key);
+ if (!value_p || *value_p != 123)
+ return XDP_DROP;

map = bpf_map_lookup_elem(&mim_hash, &key);
if (!map)
--
2.19.1