The quilt patch titled
Subject: hugetlb pages should not be reserved by shmat() if SHM_NORESERVE
has been removed from the -mm tree. Its filename was
hugetlb-pages-should-not-be-reserved-by-shmat-if-shm_noreserve.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Prakash Sangappa <prakash.sangappa@xxxxxxxxxx>
Subject: Hugetlb pages should not be reserved by shmat() if SHM_NORESERVE
Date: Fri, 19 Jan 2024 17:17:52 -0800
For shared memory of type SHM_HUGETLB, hugetlb pages are reserved in
shmget() call. If SHM_NORESERVE flags is specified then the hugetlb pages
are not reserved. However when the shared memory is attached with the
shmat() call the hugetlb pages are getting reserved incorrectly for
SHM_HUGETLB shared memory created with SHM_NORESERVE.
Ensure that the hugetlb pages are no reserved for SHM_HUGETLB shared
memory in the shmat() call.
Link: https://lkml.kernel.org/r/1705713472-3537-1-git-send-email-prakash.sangappa@xxxxxxxxxx
Signed-off-by: Prakash Sangappa <prakash.sangappa@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/fs/hugetlbfs/inode.c~hugetlb-pages-should-not-be-reserved-by-shmat-if-shm_noreserve
+++ a/fs/hugetlbfs/inode.c
@@ -141,7 +141,13 @@ static int hugetlbfs_file_mmap(struct fi
file_accessed(file);
ret = -ENOMEM;
- if (!hugetlb_reserve_pages(inode,
+
+ /*
+ * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
+ * reserving here. Note only for SHM hugetlbfs file, the inode
+ * flag S_PRIVATE is set.
+ */
+ if (!(inode->i_flags & S_PRIVATE) && !hugetlb_reserve_pages(inode,
vma->vm_pgoff >> huge_page_order(h),
len >> huge_page_shift(h), vma,
vma->vm_flags))
_
Patches currently in -mm which might be from prakash.sangappa@xxxxxxxxxx are
