From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
From: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
commit 42a382a466a967dc053c73b969cd2ac2fec502cf upstream.
test_snprintf_btf fails on s390, because NULL points to a readable
struct lowcore there. Fix by using the last page instead.
Error message example:
printing fffffffffffff000 should generate error, got (361)
Fixes: 076a95f5aff2 ("selftests/bpf: Add bpf_snprintf_btf helper tests")
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
Link: https://lore.kernel.org/bpf/20210227051726.121256-1-iii@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/bpf/progs/netif_receive_skb.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
--- a/tools/testing/selftests/bpf/progs/netif_receive_skb.c
+++ b/tools/testing/selftests/bpf/progs/netif_receive_skb.c
@@ -16,6 +16,13 @@ bool skip = false;
#define STRSIZE 2048
#define EXPECTED_STRSIZE 256
+#if defined(bpf_target_s390)
+/* NULL points to a readable struct lowcore on s390, so take the last page */
+#define BADPTR ((void *)0xFFFFFFFFFFFFF000ULL)
+#else
+#define BADPTR 0
+#endif
+
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#endif
@@ -113,11 +120,11 @@ int BPF_PROG(trace_netif_receive_skb, st
}
/* Check invalid ptr value */
- p.ptr = 0;
+ p.ptr = BADPTR;
__ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
if (__ret >= 0) {
- bpf_printk("printing NULL should generate error, got (%d)",
- __ret);
+ bpf_printk("printing %llx should generate error, got (%d)",
+ (unsigned long long)BADPTR, __ret);
ret = -ERANGE;
}
