From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
peterx@redhat.com, Axel Rasmussen <axelrasmussen@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>
Subject: [PATCH] userfaultfd/hugetlbfs: Fix minor fault page leak
Date: Mon, 22 Mar 2021 13:51:32 -0400 [thread overview]
Message-ID: <20210322175132.36659-1-peterx@redhat.com> (raw)
When uffd-minor enabled, we need to put the page cache before handling the
userfault in hugetlb_no_page(), otherwise the page refcount got leaked.
This can be reproduced by running userfaultfd selftest with hugetlb_shared
mode, then cat /proc/meminfo.
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: f2bf15fb0969 ("userfaultfd: add minor fault registration mode")
Signed-off-by: Peter Xu <peterx@redhat.com>
---
mm/hugetlb.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 408dbc08298a..56b78a206913 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4449,6 +4449,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
/* Check for page in userfault range. */
if (userfaultfd_minor(vma)) {
unlock_page(page);
+ put_page(page);
ret = hugetlb_handle_userfault(vma, mapping, idx,
flags, haddr,
VM_UFFD_MINOR);
--
2.26.2
next reply other threads:[~2021-03-22 17:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 17:51 Peter Xu [this message]
2021-03-22 20:13 ` [PATCH] userfaultfd/hugetlbfs: Fix minor fault page leak Mike Kravetz
2021-03-22 20:19 ` Axel Rasmussen
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