Commit 42a382a4 authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Daniel Borkmann
Browse files

selftests/bpf: Use the last page in test_snprintf_btf on s390 



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: 076a95f5 ("selftests/bpf: Add bpf_snprintf_btf helper tests")
Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210227051726.121256-1-iii@linux.ibm.com
parent 8811f4a9

tools/testing/selftests/bpf/progs/netif_receive_skb.c

+10 −3
Original line number Diff line number Diff line
@@ -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, struct sk_buff *skb) 
	}



	/* 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;

	}