The patch titled
Subject: mm/hugetlb: fix use after free when subpool max_hpages accounting is not enabled
has been removed from the -mm tree. Its filename was
mm-hugetlb-fix-use-after-free-when-subpool-max_hpages-accounting-is-not-enabled.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/hugetlb: fix use after free when subpool max_hpages accounting is not enabled
If a hugetlbfs filesystem is created with the min_size option and
without the size option, used_hpages is always 0 and might lead to
release subpool prematurely because it indicates no pages are used now
while there might be.
In order to fix this issue, we should check used_hpages == 0 iff
max_hpages accounting is enabled. As max_hpages accounting should be
enabled in most common case, this is not worth a Cc stable.
[mike.kravetz@xxxxxxxxxx: new changelog]
Link: https://lkml.kernel.org/r/20210126115510.53374-1-linmiaohe@xxxxxxxxxx
Signed-off-by: Hongxiang Lou <louhongxiang@xxxxxxxxxx>
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlb-fix-use-after-free-when-subpool-max_hpages-accounting-is-not-enabled
+++ a/mm/hugetlb.c
@@ -97,16 +97,26 @@ static inline void ClearPageHugeFreed(st
/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);
-static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
+static inline bool subpool_is_free(struct hugepage_subpool *spool)
{
- bool free = (spool->count == 0) && (spool->used_hpages == 0);
+ if (spool->count)
+ return false;
+ if (spool->max_hpages != -1)
+ return spool->used_hpages == 0;
+ if (spool->min_hpages != -1)
+ return spool->rsv_hpages == spool->min_hpages;
+
+ return true;
+}
+static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
+{
spin_unlock(&spool->lock);
/* If no pages are used, and no other handles to the subpool
* remain, give up any reservations based on minimum size and
* free the subpool */
- if (free) {
+ if (subpool_is_free(spool)) {
if (spool->min_hpages != -1)
hugetlb_acct_memory(spool->hstate,
-spool->min_hpages);
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-memory_hotplug-use-helper-function-zone_end_pfn-to-get-end_pfn.patch
mm-mlock-stop-counting-mlocked-pages-when-none-vma-is-found.patch
mm-rmap-correct-some-obsolete-comments-of-anon_vma.patch
mm-rmap-remove-unneeded-semicolon-in-page_not_mapped.patch
mm-rmap-fix-obsolete-comment-in-__page_check_anon_rmap.patch
mm-rmap-use-page_not_mapped-in-try_to_unmap.patch
mm-rmap-correct-obsolete-comment-of-page_get_anon_vma.patch
mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
mm-zsmallocc-convert-to-use-kmem_cache_zalloc-in-cache_alloc_zspage.patch
mm-zsmallocc-use-page_private-to-access-page-private.patch
