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Tue, 04 Aug 2026 01:41:33 -0700 (PDT) Received: from google.com ([2a00:79e0:2031:6:32eb:b46b:e9eb:65c5]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84edc29c73bsm4783637b3a.29.2026.08.04.01.41.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Aug 2026 01:41:32 -0700 (PDT) Date: Tue, 4 Aug 2026 17:41:29 +0900 From: Sergey Senozhatsky To: Longlong Xia , Andrew Morton Cc: Minchan Kim , Sergey Senozhatsky , Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Longlong Xia , stable@vger.kernel.org Subject: Re: [PATCH 1/2] zram: fix out-of-bounds access in writeback_store() Message-ID: References: <20260804065919.3970386-1-xialonglong2025@163.com> <20260804065919.3970386-2-xialonglong2025@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260804065919.3970386-2-xialonglong2025@163.com> On (26/08/04 14:59), Longlong Xia wrote: > writeback_store() calculates the table scan bounds before taking > dev_lock. A reset followed by reconfiguration with a smaller disksize > can therefore replace zram->table while writeback_store() is waiting for > the lock. Once it acquires the lock, it sees an initialized device but > scans the new table using the old upper bound, resulting in an > out-of-bounds access. > > Calculate the number of pages while holding dev_lock so the scan bound > matches the table protected by the lock. > > Fixes: a939888ec38b ("zram: support idle/huge page writeback") > Cc: > Assisted-by: Codex:gpt-5.6-sol > Signed-off-by: Longlong Xia Reviewed-by: Sergey Senozhatsky