From: Shijie Luo <luoshijie1@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
<osalvador@suse.de>, <mhocko@suse.com>, <linmiaohe@huawei.com>,
<linfeilong@huawei.com>, <luoshijie1@huawei.com>
Subject: [PATCH V2] mm: fix potential pte_unmap_unlock pte error
Date: Fri, 16 Oct 2020 22:11:51 -0400 [thread overview]
Message-ID: <20201017021151.28104-1-luoshijie1@huawei.com> (raw)
When flags don't have MPOL_MF_MOVE or MPOL_MF_MOVE_ALL bits, code breaks
and passing origin pte - 1 to pte_unmap_unlock seems like not a good idea.
Signed-off-by: Shijie Luo <luoshijie1@huawei.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/mempolicy.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3fde772ef5ef..3ca4898f3f24 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -525,7 +525,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long flags = qp->flags;
int ret;
bool has_unmovable = false;
- pte_t *pte;
+ pte_t *pte, *mapped_pte;
spinlock_t *ptl;
ptl = pmd_trans_huge_lock(pmd, vma);
@@ -539,7 +539,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
if (pmd_trans_unstable(pmd))
return 0;
- pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+ mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
if (!pte_present(*pte))
continue;
@@ -571,7 +571,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
} else
break;
}
- pte_unmap_unlock(pte - 1, ptl);
+ pte_unmap_unlock(mapped_pte, ptl);
cond_resched();
if (has_unmovable)
--
2.19.1
next reply other threads:[~2020-10-17 5:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-17 2:11 Shijie Luo [this message]
2020-10-19 6:59 ` [PATCH V2] mm: fix potential pte_unmap_unlock pte error Michal Hocko
2020-10-19 7:25 ` Shijie Luo
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