From: Greg Kroah-Hartman gregkh@linuxfoundation.org
From: Ilya Leoshkevich iii@linux.ibm.com
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@linux.ibm.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Heiko Carstens hca@linux.ibm.com Acked-by: Yonghong Song yhs@fb.com Link: https://lore.kernel.org/bpf/20210227051726.121256-1-iii@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }