linux-kernel - [PATCH v4 09/11 fix] fix: mm: pgtable: reclaim empty PTE page in madvise(MADV

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Message-Id: <20241206112348.51570-1-zhengqi.arch@bytedance.com>
Date: Fri,  6 Dec 2024 19:23:48 +0800
From: Qi Zheng <zhengqi.arch@...edance.com>
To: akpm@...ux-foundation.org,
	dan.carpenter@...aro.org
Cc: linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Qi Zheng <zhengqi.arch@...edance.com>
Subject: [PATCH v4 09/11 fix] fix: mm: pgtable: reclaim empty PTE page in madvise(MADV_DONTNEED)

Dan Carpenter reported the following warning:

Commit e3aafd2d3551 ("mm: pgtable: reclaim empty PTE page in
madvise(MADV_DONTNEED)") from Dec 4, 2024 (linux-next), leads to the
following Smatch static checker warning:

	mm/pt_reclaim.c:69 try_to_free_pte()
	error: uninitialized symbol 'ptl'.

To fix it, assign an initial value of NULL to the ptl.

Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Closes: https://lore.kernel.org/linux-mm/224e6a4e-43b5-4080-bdd8-b0a6fb2f0853@stanley.mountain/
Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
---
 mm/pt_reclaim.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/pt_reclaim.c b/mm/pt_reclaim.c
index 6540a3115dde8..7e9455a18aae7 100644
--- a/mm/pt_reclaim.c
+++ b/mm/pt_reclaim.c
@@ -36,7 +36,7 @@ void try_to_free_pte(struct mm_struct *mm, pmd_t *pmd, unsigned long addr,
 		     struct mmu_gather *tlb)
 {
 	pmd_t pmdval;
-	spinlock_t *pml, *ptl;
+	spinlock_t *pml, *ptl = NULL;
 	pte_t *start_pte, *pte;
 	int i;
 
-- 
2.20.1