It is counterintuitive at best that mmap'ing a hugetlbfs file with
MAP_HUGETLB fails, while mmap'ing it without will a) succeed and b)
return huge pages.
v2: use is_file_hugepages(), as suggested by Jianguo
Signed-off-by: Joern Engel <jo...@logfs.org>
Cc: Jianguo Wu <wujian...@huawei.com>
---
mm/mmap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 2a594246..cdc8e7a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1322,11 +1322,12 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr,
unsigned long, len,
if (!(flags & MAP_ANONYMOUS)) {
audit_mmap_fd(fd, flags);
- if (unlikely(flags & MAP_HUGETLB))
- return -EINVAL;
file = fget(fd);
if (!file)
goto out;
+ retval = -EINVAL;
+ if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
+ goto out_fput;
} else if (flags & MAP_HUGETLB) {
struct user_struct *user = NULL;
/*
@@ -1346,6 +1347,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned
long, len,
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+out_fput:
if (file)
fput(file);
out:
--
1.7.10.4
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