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mm/hugetlb: fix incorrect error return from hugetlb_reserve_pages() 

The function hugetlb_reserve_pages() returns the number of pages added
to the reservation map on success and a negative error code on failure
(e.g. -EINVAL, -ENOMEM). However, in some error paths, it may return -1
directly.

For example, a failure at:

    if (hugetlb_acct_memory(h, gbl_reserve) < 0)
        goto out_put_pages;

results in returning -1 (since add = -1), which may be misinterpreted
in userspace as -EPERM.

Fix this by explicitly capturing and propagating the return values from
helper functions, and using -EINVAL for all other failure cases.

Link: https://lkml.kernel.org/r/20251125171350.86441-1-skolothumtho@nvidia.com
Fixes: 986f5f2b4b ("mm/hugetlb: make hugetlb_reserve_pages() return nr of entries updated")
Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew R. Ochs <mochs@nvidia.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolin Chen <nicolinc@nvidia.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
master
Shameer Kolothum 2025-11-25 17:13:50 +00:00 committed by Andrew Morton
parent 40a4af52e0
commit 9ee5d1766c
1 changed files with 18 additions and 7 deletions
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25
mm/hugetlb.c
View File

@ -6579,6 +6579,7 @@ long hugetlb_reserve_pages(struct inode *inode,
struct resv_map *resv_map;
struct hugetlb_cgroup *h_cg = NULL;
long gbl_reserve, regions_needed = 0;
int err;
/* This should never happen */
if (from > to) {
@ -6612,8 +6613,10 @@ long hugetlb_reserve_pages(struct inode *inode,
} else {
/* Private mapping. */
resv_map = resv_map_alloc();
if (!resv_map)
if (!resv_map) {
err = -ENOMEM;
goto out_err;
}
chg = to - from;
@ -6621,11 +6624,15 @@ long hugetlb_reserve_pages(struct inode *inode,
set_vma_desc_resv_flags(desc, HPAGE_RESV_OWNER);
}
if (chg < 0)
if (chg < 0) {
/* region_chg() above can return -ENOMEM */
err = (chg == -ENOMEM) ? -ENOMEM : -EINVAL;
goto out_err;
}
if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
chg * pages_per_huge_page(h), &h_cg) < 0)
err = hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
chg * pages_per_huge_page(h), &h_cg);
if (err < 0)
goto out_err;
if (desc && !(desc->vm_flags & VM_MAYSHARE) && h_cg) {
@ -6641,14 +6648,17 @@ long hugetlb_reserve_pages(struct inode *inode,
* reservations already in place (gbl_reserve).
*/
gbl_reserve = hugepage_subpool_get_pages(spool, chg);
if (gbl_reserve < 0)
if (gbl_reserve < 0) {
err = gbl_reserve;
goto out_uncharge_cgroup;
}
/*
* Check enough hugepages are available for the reservation.
* Hand the pages back to the subpool if there are not
*/
if (hugetlb_acct_memory(h, gbl_reserve) < 0)
err = hugetlb_acct_memory(h, gbl_reserve);
if (err < 0)
goto out_put_pages;
/*
@ -6667,6 +6677,7 @@ long hugetlb_reserve_pages(struct inode *inode,
if (unlikely(add < 0)) {
hugetlb_acct_memory(h, -gbl_reserve);
err = add;
goto out_put_pages;
} else if (unlikely(chg > add)) {
/*
@ -6726,7 +6737,7 @@ out_err:
kref_put(&resv_map->refs, resv_map_release);
set_vma_desc_resv_map(desc, NULL);
}
return chg < 0 ? chg : add < 0 ? add : -EINVAL;
return err;
}
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,