linux-kernel - [PATCH] arm64: mm: use ptep_clear() instead of pte_clear() in clear

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Message-Id: <20230810093241.1181142-1-qi.zheng@linux.dev>
Date:   Thu, 10 Aug 2023 09:32:41 +0000
From:   Qi Zheng <qi.zheng@...ux.dev>
To:     catalin.marinas@....com, will@...nel.org,
        akpm@...ux-foundation.org, wangkefeng.wang@...wei.co,
        pasha.tatashin@...een.com, muchun.song@...ux.dev
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Qi Zheng <zhengqi.arch@...edance.com>
Subject: [PATCH] arm64: mm: use ptep_clear() instead of pte_clear() in clear_flush()

From: Qi Zheng <zhengqi.arch@...edance.com>

In clear_flush(), the original pte may be a present entry, so we should
use ptep_clear() to let page_table_check track the pte clearing operation,
otherwise it may cause false positive in subsequent set_pte_at().

Fixes: 42b2547137f5 ("arm64/mm: enable ARCH_SUPPORTS_PAGE_TABLE_CHECK")
Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
---
 arch/arm64/mm/hugetlbpage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 21716c940682..9c52718ea750 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -236,7 +236,7 @@ static void clear_flush(struct mm_struct *mm,
 	unsigned long i, saddr = addr;
 
 	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
-		pte_clear(mm, addr, ptep);
+		ptep_clear(mm, addr, ptep);
 
 	flush_tlb_range(&vma, saddr, addr);
 }
-- 
2.30.2