From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 94C1E2F746D; Fri, 3 Apr 2026 16:20:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775233252; cv=none; b=G9+JvhB2QlEu4GNDRE705g0Dn5Nflv2mvOKi/I35flxGdGipTEM8vJc3DA418rNGqah0NRYZV6s/kuR2B1/sn0sRVpYgku9+s+IRvn9XZXNougv0hzXcwVgmJiH47b+qsWVCw6xd7Edu5Qz/uPUiZsqXCdVxOqfHDQHAA2Xub54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775233252; c=relaxed/simple; bh=Ds4Y+cyyYXN24nPdjxMnzx1viX9Vnik98lXxpbdexNg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Js8x14Censp26KWSH1MrZ3TY2VsDW3Pm1wqWIPgOdGCK9i8lwnzMhaa/mwOUCTD+HgVr1CcbbtWnkCrWQnEo7rt+BDrjSUEb5cEtLJtI1SmWgpT+9EvbURyaEvvvl1agoOP6LQQU7RY74kKaCGKopdvZx13xrrHC2lcSNLDzgNc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jBzEjqFJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jBzEjqFJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9875C4CEF7; Fri, 3 Apr 2026 16:20:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775233252; bh=Ds4Y+cyyYXN24nPdjxMnzx1viX9Vnik98lXxpbdexNg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jBzEjqFJ1M2qH9kDhXArAiBA52bw9oPlUpcxKq2q+U/lWvaDw3J8QC8jOFGh/G/lf KfdobvROy4Jj/QIhPTA1+wq8v2MxUx8UyMZS6zYFcxoLUzvEJrV800sceWdXm1rHxT JrJ1siN49rXwG/EHOhrNymsDa6vV9ExazJceml+wMWRIKeYha4V7yZI61dItQbTA4w rUz5HMe401+QZvGMqjIDijYrgVYdLUVF1q6PY81MiaJlC+DK7wqsz2/PUPLVjxqH3E kpo0I1RnHUnYlVgtOsfaadZJVGoGVS0vlmGy2rNsekQRKmMC4/yLa7U4mMrS/ORDIE T+xNsYlufIonA== From: SeongJae Park To: Liew Rui Yan Cc: SeongJae Park , yanquanmin1@huawei.com, damon@lists.linux.dev, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [PATCH v3 2/2] mm/damon/reclaim: validate min_region_size to be power of 2 Date: Fri, 3 Apr 2026 09:20:50 -0700 Message-ID: <20260403162050.65121-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260403052837.58063-3-aethernet65535@gmail.com> References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Fri, 3 Apr 2026 13:23:50 +0800 Liew Rui Yan wrote: > The damon_commit_ctx() checks if 'min_region_sz' is a power-of-2. > However, if an invalid input is provided via the DAMON_RECLAIM interface, > the validation failure occurs too late, causing kdamond to terminate > unexpectedly. > > To reproduce: > 1. Enable DAMON_RECLAIM. > 2. Set an invalid 'addr_unit' (e.g., addr_unit=3) so that > 'min_region_sz = DAMON_MIN_REGION_SZ / addr_unit' becomes > non-power-of-2. > 3. Commit parameters, and observe kdamond termination. > > This patch adds an early check in damon_reclaim_apply_parameters() to > validate 'min_region_sz' and return -EINVAL immediately if it is not a > power-of-2, preventing unexpected kdamond termination. > > Fixes: 7db551fcfb2a ("mm/damon/reclaim: support addr_unit for DAMON_RECLAIM") > Cc: # 6.18.x I'm not very sure if this deserves Cc-ing stable@. I posted more details on my reply to the first patch of this series. Let's discuss further on the thread. I will skip reviewing this patch until the discussion on the thread is done. Thanks, SJ [...]