From: Christophe Leroy christophe.leroy@c-s.fr Subject: selftests/vm: fix map_hugetlb length used for testing read and write

Commit fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb") added the possibility to change the size of memory mapped for the test, but left the read and write test using the default value. This is unnoticed when mapping a length greater than the default one, but segfaults otherwise.

Fix read_bytes() and write_bytes() by giving them the real length.

Also fix the call to munmap().

Link: http://lkml.kernel.org/r/9a404a13c871c4bd0ba9ede68f69a1225180dd7e.1580978385... Fixes: fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb") Signed-off-by: Christophe Leroy christophe.leroy@c-s.fr Reviewed-by: Leonardo Bras leonardo@linux.ibm.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

tools/testing/selftests/vm/map_hugetlb.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/tools/testing/selftests/vm/map_hugetlb.c~selftests-vm-fix-map_hugetlb-length-used-for-testing-read-and-write +++ a/tools/testing/selftests/vm/map_hugetlb.c @@ -45,20 +45,20 @@ static void check_bytes(char *addr) printf("First hex is %x\n", *((unsigned int *)addr)); }

-static void write_bytes(char *addr) +static void write_bytes(char *addr, size_t length) { unsigned long i;

- for (i = 0; i < LENGTH; i++) + for (i = 0; i < length; i++) *(addr + i) = (char)i; }

-static int read_bytes(char *addr) +static int read_bytes(char *addr, size_t length) { unsigned long i;

check_bytes(addr); - for (i = 0; i < LENGTH; i++) + for (i = 0; i < length; i++) if (*(addr + i) != (char)i) { printf("Mismatch at %lu\n", i); return 1; @@ -96,11 +96,11 @@ int main(int argc, char **argv)

printf("Returned address is %p\n", addr); check_bytes(addr); - write_bytes(addr); - ret = read_bytes(addr); + write_bytes(addr, length); + ret = read_bytes(addr, length);

/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */ - if (munmap(addr, LENGTH)) { + if (munmap(addr, length)) { perror("munmap"); exit(1); } _