hugetlb: add new testcase hugeshmat05.c

shmget()/shmat() fails to allocate huge pages shared memory segment with EINVAL if its size is not in the range [ N*HUGE_PAGE_SIZE - 4095, N*HUGE_PAGE_SIZE ]. This is a problem in the memory segment size round up algorithm. The requested size is rounded up to PAGE_SIZE (4096), but if this roundup does not match HUGE_PAGE_SIZE (2Mb) boundary - the allocation fails.

This bug is present in all RHEL6 versions, but not in RHEL7. It looks like this was fixed in mainstream kernel > v3.3 by the following patches:

091d0d5 shm: fix null pointer deref when userspace specifies invalid hugepage size af73e4d hugetlbfs: fix mmap failure in unaligned size request
42d7395 mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB 40716e2 hugetlbfs: fix alignment of huge page requests

---

Notes:
v2 --> v3
- remove the redundant code comments
- set the test sizes in array tst_sizes[]

 runtest/hugetlb                                    |   1 +
 testcases/kernel/mem/.gitignore                    |   1 +
 .../kernel/mem/hugetlb/hugeshmat/hugeshmat05.c     | 135 +++++++++++++++++++++
 3 files changed, 137 insertions(+)
 create mode 100644 testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat05.c

index 2e9f215..75e6426 100644
@@ -10,6 +10,7 @@ hugeshmat01 hugeshmat01 -i 5
 hugeshmat02 hugeshmat02 -i 5
 hugeshmat03 hugeshmat03 -i 5
 hugeshmat04 hugeshmat04 -i 5
+hugeshmat05 hugeshmat05 -i 5
 
 hugeshmctl01 hugeshmctl01 -i 5
 hugeshmctl02 hugeshmctl02 -i 5

index 4702377..46c2432 100644
@@ -7,6 +7,7 @@
 /hugetlb/hugeshmat/hugeshmat02
 /hugetlb/hugeshmat/hugeshmat03
 /hugetlb/hugeshmat/hugeshmat04
+/hugetlb/hugeshmat/hugeshmat05
 /hugetlb/hugeshmctl/hugeshmctl01
 /hugetlb/hugeshmctl/hugeshmctl02
 /hugetlb/hugeshmctl/hugeshmctl03

1.8.3.1

Hi,

Applied, thanks!

Also fixed some style warns and errors:

ERROR: need consistent spacing around '-' (ctx:WxV)
#177: FILE: testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat05.c:119:
+ N * hpage_size - page_size -1,

ERROR: space required before the open parenthesis '(' #185: FILE: testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat05.c:127:
+ for(i = 0; i < ARRAY_SIZE(tst_sizes); ++i)

Thanks,
Alexey