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Mon, 17 Nov 2025 23:52:28 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:beba:22fc:d89b:ce14]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7b924aee147sm15609775b3a.13.2025.11.17.23.52.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Nov 2025 23:52:27 -0800 (PST) Date: Tue, 18 Nov 2025 16:52:23 +0900 From: Sergey Senozhatsky To: Yuwen Chen Cc: senozhatsky@chromium.org, akpm@linux-foundation.org, bgeffon@google.com, licayy@outlook.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, minchan@kernel.org, richardycc@google.com Subject: Re: [PATCH] zram: Fix the issue that the write - back limits might overflow Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 402B910000E X-Stat-Signature: wwseqz6pgn8bskshecesbrn7n7ihpdj6 X-Rspam-User: X-HE-Tag: 1763452349-323326 X-HE-Meta: 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 qgMFN9tE gdJS9ZpgCE93YrEKZP0/cmKfdRw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On (25/11/18 15:39), Yuwen Chen wrote: > Since the value of bd_wb_limit is an unsigned number, when the > page size is larger than 4 KB, it may cause an out-of-bounds situation. > > This patch fixes the issue by limiting bd_wb_limit to be an > integer multiple of PAGE_SIZE / 4096. I really wish we could just change wb code to use PAGE_SIZE not 4K units [1], unfortunately it's probably too late to change that now. [1] https://lore.kernel.org/linux-kernel/20251110052741.92031-1-senozhatsky@chromium.org