[patch 47/54] selftest/mremap_test: avoid crash with static build

From: "Aneesh Kumar K.V" <redacted>
Subject: selftest/mremap_test: avoid crash with static build

With a large mmap map size, we can overlap with the text area and using
MAP_FIXED results in unmapping that area.  Switch to MAP_FIXED_NOREPLACE
and handle the EEXIST error.

Link: https://lkml.kernel.org/r/20210616045239.370802-3-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <redacted>
Reviewed-by: Kalesh Singh <redacted>
Cc: Christophe Leroy <redacted>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joel Fernandes <redacted>
Cc: Kirill A. Shutemov <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Stephen Rothwell <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/vm/mremap_test.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/tools/testing/selftests/vm/mremap_test.c~selftest-mremap_test-avoid-crash-with-static-build
+++ a/tools/testing/selftests/vm/mremap_test.c

@@ -75,9 +75,10 @@ static void *get_source_mapping(struct c
 retry:
 	addr += c.src_alignment;
 	src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE,
-			MAP_FIXED | MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+			MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED,
+			-1, 0);
 	if (src_addr == MAP_FAILED) {
-		if (errno == EPERM)
+		if (errno == EPERM || errno == EEXIST)
 			goto retry;
 		goto error;
 	}

_