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Mon, 16 Jun 2025 19:05:55 -0700 (PDT) Received: from EBJ9932692.tcent.cn ([103.88.46.15]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-313c1b4993fsm9421536a91.30.2025.06.16.19.05.50 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 16 Jun 2025 19:05:55 -0700 (PDT) From: Lance Yang X-Google-Original-From: Lance Yang To: akpm@linux-foundation.org Cc: 21cnbao@gmail.com, david@redhat.com, Liam.Howlett@oracle.com, vbabka@suse.cz, jannh@google.com, lorenzo.stoakes@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Lance Yang Subject: [PATCH 1/1] mm/madvise: initialize prev pointer in madvise_walk_vmas Date: Tue, 17 Jun 2025 10:05:43 +0800 Message-ID: <20250617020544.57305-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Lance Yang The prev pointer was uninitialized, which could lead to undefined behavior where its address is taken and passed to the visit() callback without being assigned a value. Initializing it to NULL makes the code safer and prevents potential bugs if a future callback function attempts to read from it. Signed-off-by: Lance Yang --- mm/madvise.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 267d8e4adf31..c87325000303 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1536,10 +1536,10 @@ int madvise_walk_vmas(struct mm_struct *mm, unsigned long start, struct vm_area_struct **prev, unsigned long start, unsigned long end, void *arg)) { + struct vm_area_struct *prev = NULL; struct vm_area_struct *vma; - struct vm_area_struct *prev; - unsigned long tmp; int unmapped_error = 0; + unsigned long tmp; int error; /* -- 2.49.0