2018-02-28 04:05:29

by Aneesh Kumar K.V

Subject: [PATCH] selftests/vm: Update max va test to check for high address return.

mmap(-1,..) is expected to search from max supported VA top down. It should find
an address above ADDR_SWITCH_HINT. Explicitly check for this.

Also derefer the address even if we failed the addr check.

Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
tools/testing/selftests/vm/va_128TBswitch.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/vm/va_128TBswitch.c b/tools/testing/selftests/vm/va_128TBswitch.c
index e7fe734c374f..f68fa4bd8179 100644
--- a/tools/testing/selftests/vm/va_128TBswitch.c
+++ b/tools/testing/selftests/vm/va_128TBswitch.c
@@ -44,6 +44,7 @@ struct testcase {
unsigned long flags;
const char *msg;
unsigned int low_addr_required:1;
+ unsigned int high_addr_required:1;
unsigned int keep_mapped:1;
};

@@ -108,6 +109,7 @@ static struct testcase testcases[] = {
.flags = MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(HIGH_ADDR)",
.keep_mapped = 1,
+ .high_addr_required = 1,
},
{
.addr = HIGH_ADDR,
@@ -115,12 +117,14 @@ static struct testcase testcases[] = {
.flags = MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(HIGH_ADDR) again",
.keep_mapped = 1,
+ .high_addr_required = 1,
},
{
.addr = HIGH_ADDR,
.size = 2 * PAGE_SIZE,
.flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
.msg = "mmap(HIGH_ADDR, MAP_FIXED)",
+ .high_addr_required = 1,
},
{
.addr = (void *) -1,
@@ -128,12 +132,14 @@ static struct testcase testcases[] = {
.flags = MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(-1)",
.keep_mapped = 1,
+ .high_addr_required = 1,
},
{
.addr = (void *) -1,
.size = 2 * PAGE_SIZE,
.flags = MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(-1) again",
+ .high_addr_required = 1,
},
{
.addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)),
@@ -193,6 +199,7 @@ static struct testcase hugetlb_testcases[] = {
.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(HIGH_ADDR, MAP_HUGETLB)",
.keep_mapped = 1,
+ .high_addr_required = 1,
},
{
.addr = HIGH_ADDR,
@@ -200,12 +207,14 @@ static struct testcase hugetlb_testcases[] = {
.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(HIGH_ADDR, MAP_HUGETLB) again",
.keep_mapped = 1,
+ .high_addr_required = 1,
},
{
.addr = HIGH_ADDR,
.size = HUGETLB_SIZE,
.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
.msg = "mmap(HIGH_ADDR, MAP_FIXED | MAP_HUGETLB)",
+ .high_addr_required = 1,
},
{
.addr = (void *) -1,
@@ -213,12 +222,14 @@ static struct testcase hugetlb_testcases[] = {
.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(-1, MAP_HUGETLB)",
.keep_mapped = 1,
+ .high_addr_required = 1,
},
{
.addr = (void *) -1,
.size = HUGETLB_SIZE,
.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
.msg = "mmap(-1, MAP_HUGETLB) again",
+ .high_addr_required = 1,
},
{
.addr = (void *)(ADDR_SWITCH_HINT - PAGE_SIZE),
@@ -257,14 +268,16 @@ static int run_test(struct testcase *test, int count)
if (t->low_addr_required && p >= (void *)(ADDR_SWITCH_HINT)) {
printf("FAILED\n");
ret = 1;
- } else {
- /*
- * Do a dereference of the address returned so that we catch
- * bugs in page fault handling
- */
- memset(p, 0, t->size);
+ } else if (t->high_addr_required && p < (void *)(ADDR_SWITCH_HINT)) {
+ printf("FAILED\n");
+ ret = 1;
+ } else
printf("OK\n");
- }
+ /*
+ * Do a dereference of the address returned so that we catch
+ * bugs in page fault handling
+ */
+ memset(p, 0, t->size);
if (!t->keep_mapped)
munmap(p, t->size);
}
--
2.14.3

2018-02-28 08:10:38

by Aneesh Kumar K.V

Subject: Re: [PATCH] selftests/vm: Update max va test to check for high address return.

"Aneesh Kumar K.V" <[email protected]> writes:

> mmap(-1,..) is expected to search from max supported VA top down. It should find
> an address above ADDR_SWITCH_HINT. Explicitly check for this.
>
> Also derefer the address even if we failed the addr check.
>
> Signed-off-by: Aneesh Kumar K.V <[email protected]>

One issue I noticed is how to make this conditional so that we can still
run the test on x86 with 4 level page table?

> ---
> tools/testing/selftests/vm/va_128TBswitch.c | 27 ++++++++++++++++++++-------
> 1 file changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/va_128TBswitch.c b/tools/testing/selftests/vm/va_128TBswitch.c
> index e7fe734c374f..f68fa4bd8179 100644
> --- a/tools/testing/selftests/vm/va_128TBswitch.c
> +++ b/tools/testing/selftests/vm/va_128TBswitch.c
> @@ -44,6 +44,7 @@ struct testcase {
> unsigned long flags;
> const char *msg;
> unsigned int low_addr_required:1;
> + unsigned int high_addr_required:1;
> unsigned int keep_mapped:1;
> };
>
> @@ -108,6 +109,7 @@ static struct testcase testcases[] = {
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> @@ -115,12 +117,14 @@ static struct testcase testcases[] = {
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR) again",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> .size = 2 * PAGE_SIZE,
> .flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> .msg = "mmap(HIGH_ADDR, MAP_FIXED)",
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> @@ -128,12 +132,14 @@ static struct testcase testcases[] = {
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> .size = 2 * PAGE_SIZE,
> .flags = MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1) again",
> + .high_addr_required = 1,
> },
> {
> .addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)),
> @@ -193,6 +199,7 @@ static struct testcase hugetlb_testcases[] = {
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR, MAP_HUGETLB)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> @@ -200,12 +207,14 @@ static struct testcase hugetlb_testcases[] = {
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(HIGH_ADDR, MAP_HUGETLB) again",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = HIGH_ADDR,
> .size = HUGETLB_SIZE,
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> .msg = "mmap(HIGH_ADDR, MAP_FIXED | MAP_HUGETLB)",
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> @@ -213,12 +222,14 @@ static struct testcase hugetlb_testcases[] = {
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1, MAP_HUGETLB)",
> .keep_mapped = 1,
> + .high_addr_required = 1,
> },
> {
> .addr = (void *) -1,
> .size = HUGETLB_SIZE,
> .flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> .msg = "mmap(-1, MAP_HUGETLB) again",
> + .high_addr_required = 1,
> },
> {
> .addr = (void *)(ADDR_SWITCH_HINT - PAGE_SIZE),
> @@ -257,14 +268,16 @@ static int run_test(struct testcase *test, int count)
> if (t->low_addr_required && p >= (void *)(ADDR_SWITCH_HINT)) {
> printf("FAILED\n");
> ret = 1;
> - } else {
> - /*
> - * Do a dereference of the address returned so that we catch
> - * bugs in page fault handling
> - */
> - memset(p, 0, t->size);
> + } else if (t->high_addr_required && p < (void *)(ADDR_SWITCH_HINT)) {
> + printf("FAILED\n");
> + ret = 1;
> + } else
> printf("OK\n");
> - }
> + /*
> + * Do a dereference of the address returned so that we catch
> + * bugs in page fault handling
> + */
> + memset(p, 0, t->size);
> if (!t->keep_mapped)
> munmap(p, t->size);
> }
> --
> 2.14.3
>
> --
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2018-02-28 11:00:04

by Kirill A. Shutemov

Subject: Re: [PATCH] selftests/vm: Update max va test to check for high address return.

On Wed, Feb 28, 2018 at 09:28:30AM +0530, Aneesh Kumar K.V wrote:
> mmap(-1,..) is expected to search from max supported VA top down. It should find
> an address above ADDR_SWITCH_HINT. Explicitly check for this.

Hm. I don't think this correct. -1 means the application supports any
address, not restricted to 47-bit address space. It doesn't mean the
application *require* the address to be above 47-bit.

At least on x86, -1 just shift upper boundary of address range where we
can look for unmapped area.

--
Kirill A. Shutemov