Re: [PATCH] selftests/vm: Set mmap()'s fd as -1 for MAP_ANONYMOUS flag
From: Shuah Khan
Date: Fri Mar 24 2017 - 12:48:10 EST
On 03/22/2017 07:09 PM, SeongJae Park wrote:
> Hello Shuah,
>
>
> May I ask some comments?
>
>
> Thanks,
> SeongJae Park
>
> On Wed, Mar 15, 2017 at 10:19 PM, SeongJae Park <sj38.park@xxxxxxxxx> wrote:
>> Man page of mmap() says that portable applications should ensure fd
>> argument to be -1 if MAP_ANONYMOUS flag is set as below:
>> ```
>> The mapping is not backed by any file; its contents are initialized to
>> zero. The fd and offset arguments are ignored; however, some
>> implementations require fd to be -1 if MAP_ANONYMOUS (or
>> MAP_ANON) is specified, and portable applications
>> should ensure this.
>> ```
>>
>> However, few mmap() calls under selftests/vm/ uses 0 as fd though they
>> use MAP_ANONYMOUS flag. This commit changes the argument to be -1 as
>> recommended.
Hi Andrew,
Do you have comments on this patch? Please Ack it if you would
like me to take it thorugh ksefltest tree.
thanks,
-- Shuah
>>
>> Signed-off-by: SeongJae Park <sj38.park@xxxxxxxxx>
>> ---
>> tools/testing/selftests/vm/map_hugetlb.c | 2 +-
>> tools/testing/selftests/vm/mlock2-tests.c | 12 ++++++------
>> tools/testing/selftests/vm/on-fault-limit.c | 2 +-
>> tools/testing/selftests/vm/thuge-gen.c | 2 +-
>> 4 files changed, 9 insertions(+), 9 deletions(-)
>>
>> diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c
>> index addcd6fc1ecc..77687ab59f77 100644
>> --- a/tools/testing/selftests/vm/map_hugetlb.c
>> +++ b/tools/testing/selftests/vm/map_hugetlb.c
>> @@ -62,7 +62,7 @@ int main(void)
>> void *addr;
>> int ret;
>>
>> - addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, 0, 0);
>> + addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, -1, 0);
>> if (addr == MAP_FAILED) {
>> perror("mmap");
>> exit(1);
>> diff --git a/tools/testing/selftests/vm/mlock2-tests.c b/tools/testing/selftests/vm/mlock2-tests.c
>> index ff0cda2b19c9..e5dbc87b4297 100644
>> --- a/tools/testing/selftests/vm/mlock2-tests.c
>> +++ b/tools/testing/selftests/vm/mlock2-tests.c
>> @@ -293,7 +293,7 @@ static int test_mlock_lock()
>> unsigned long page_size = getpagesize();
>>
>> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
>> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>> if (map == MAP_FAILED) {
>> perror("test_mlock_locked mmap");
>> goto out;
>> @@ -402,7 +402,7 @@ static int test_mlock_onfault()
>> unsigned long page_size = getpagesize();
>>
>> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
>> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>> if (map == MAP_FAILED) {
>> perror("test_mlock_locked mmap");
>> goto out;
>> @@ -445,7 +445,7 @@ static int test_lock_onfault_of_present()
>> uint64_t page1_flags, page2_flags;
>>
>> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
>> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>> if (map == MAP_FAILED) {
>> perror("test_mlock_locked mmap");
>> goto out;
>> @@ -492,7 +492,7 @@ static int test_munlockall()
>> unsigned long page_size = getpagesize();
>>
>> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
>> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>>
>> if (map == MAP_FAILED) {
>> perror("test_munlockall mmap");
>> @@ -518,7 +518,7 @@ static int test_munlockall()
>> munmap(map, 2 * page_size);
>>
>> map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
>> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>>
>> if (map == MAP_FAILED) {
>> perror("test_munlockall second mmap");
>> @@ -573,7 +573,7 @@ static int test_vma_management(bool call_mlock)
>> struct vm_boundaries page3;
>>
>> map = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
>> - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
>> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>> if (map == MAP_FAILED) {
>> perror("mmap()");
>> return ret;
>> diff --git a/tools/testing/selftests/vm/on-fault-limit.c b/tools/testing/selftests/vm/on-fault-limit.c
>> index 0ae458f32fdb..7f96a5c2e292 100644
>> --- a/tools/testing/selftests/vm/on-fault-limit.c
>> +++ b/tools/testing/selftests/vm/on-fault-limit.c
>> @@ -26,7 +26,7 @@ static int test_limit(void)
>> }
>>
>> map = mmap(NULL, 2 * lims.rlim_max, PROT_READ | PROT_WRITE,
>> - MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, 0, 0);
>> + MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
>> if (map != MAP_FAILED)
>> printf("mmap should have failed, but didn't\n");
>> else {
>> diff --git a/tools/testing/selftests/vm/thuge-gen.c b/tools/testing/selftests/vm/thuge-gen.c
>> index 0bc737a75150..88a2ab535e01 100644
>> --- a/tools/testing/selftests/vm/thuge-gen.c
>> +++ b/tools/testing/selftests/vm/thuge-gen.c
>> @@ -146,7 +146,7 @@ void test_mmap(unsigned long size, unsigned flags)
>>
>> before = read_free(size);
>> map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE,
>> - MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, 0, 0);
>> + MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, -1, 0);
>>
>> if (map == (char *)-1) err("mmap");
>> memset(map, 0xff, size*NUM_PAGES);
>> --
>> 2.10.0
>>
>
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