testcases/kernel/mem/vma/vma01.c: fix the right start/end memory address

For a VMA with memory range 6*ps, regardless of it's two 3*ps or one single 6*ps, t is the start addr of the vma, u = t + 3*ps, and the end addr is t + 6*ps.

For the check process, x should start from t, not u, and later check for the second 3*ps should resume from u.

---
 testcases/kernel/mem/vma/vma01.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

index 398d7a1..4b66121 100644
@@ -112,12 +112,12 @@ static void check_vma(void)
 		printf("child : u = %p\n", u);
 		memset(u, 2, ps);
 
-		x = get_end_addr(u, MAPS_FILE);
-		if (x == u + 6*ps)
+		x = get_end_addr(t, MAPS_FILE);
+		if (x == t + 6*ps)
 			exit(1);
-		if (x == u + 3*ps) {
-			y = get_end_addr(x, MAPS_FILE);
-			if (y == x + 3*ps)
+		if (x == u) {
+			y = get_end_addr(u, MAPS_FILE);
+			if (y == u + 3*ps)
 				exit(0);
 		}
 		exit(255);

1.7.1

------------------------------------------------------------------------------
This SF email is sponsosred by:
Try Windows Azure free for 90 days Click Here 
http://p.sf.net/sfu/sfd2d-msazure
_______________________________________________
Ltp-list mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/ltp-list

Hi Shenghui, thanks for the patch.

However, your patch doesn't work in some situation, e.g.: when t mmapped at highest addr (it is the most common situation), which makes t+3*ps over boundary, so mmap will map to another addr near t+3*ps. So I propose for the following increment fix:

static void check_vma(void)

 {
        int status;

- void *t, *u, *x, *y;
+ void *t, *u, *v, *x, *y;

-       t = mmap(NULL, 3*ps, PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, 0, 0);
+       v = mmap(NULL, ps, PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, 0, 0);
+       if (v == MAP_FAILED)
+               tst_brkm(TBROK|TERRNO, cleanup, "mmap");
+       t = mmap(v - 6*ps, 3*ps, PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
0, 0);
        if (t == MAP_FAILED)
                tst_brkm(TBROK|TERRNO, cleanup, "mmap");
        memset(t, 1, ps);

A new addr v introduced before other mappings, used to locate the highest addr. And in order not to be merged with other mappings, v is mapped with READ-only prot.

result using your patch w/o my increment patch:

# ./vma01
parent: t = 0x7f82dd437000
child : u = 0x7f82dd434000
vma01       0  TINFO  :  s = 0x7f82dd437000, t = 0x7f82dd43a000
vma01       1  TBROK  :  unexpected VMA found.
vma01       2  TBROK  :  Remaining cases broken

result using your patch w/ my increment patch:

# ./vma01
parent: t = 0x7f418066f000
child : u = 0x7f4180672000
vma01       0  TINFO  :  s = 0x7f418066f000, t = 0x7f4180672000
vma01       0  TINFO  :  s = 0x7f4180672000, t = 0x7f4180675000
vma01       1  TPASS  :  two 3*ps VMAs found.

Thoughts?

Thanks,
Caspar