From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 65A67C44520 for ; Sat, 18 Jul 2026 01:03:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 358E86B0110; Fri, 17 Jul 2026 21:03:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 307106B0111; Fri, 17 Jul 2026 21:03:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 21E1F6B0112; Fri, 17 Jul 2026 21:03:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id EDAB46B0110 for ; Fri, 17 Jul 2026 21:03:23 -0400 (EDT) Received: from smtpin25.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 748EF160282 for ; Sat, 18 Jul 2026 01:03:23 +0000 (UTC) X-FDA: 85000099086.25.36FC591 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf07.hostedemail.com (Postfix) with ESMTP id D8EC340009 for ; Sat, 18 Jul 2026 01:03:21 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MtgFufK8; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf07.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1784336601; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Q6G9ezbIlMVkU6BcAV6AfIPu4SPtlwXOdQ5VEzE5oyQ=; b=Y9rtyELr43OReNP/ZMYqvafnE3NV0aZ0uYaEsp17726qliIBD38ftu7RvxQghRA+k2fhcz 4OhufdAQLLLPOk0YGbmYu7SKkdTfFWmVGkI33o18RBWp9erEHmDnZZ5ki79D6smfbF4xn6 m1xup2C5s9pl0fjIJDDhdZffp3MbqF0= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MtgFufK8; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf07.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1784336601; b=YVHfjuW9WOB/cbIP5SUb8SmgRZRe5n9J+2BJmPCTWvF+mMSVsO+RIbEunUJJtB1Ti8A3Gz c6CEVd0NjiEEwV8y4S2MqdJFyXCzTwr23TTSAuccaUVO2J7ju+5j01jTivGSU8klZ45PFZ S+QrghdtTHSMFxrrP4YGQNIjFomKzFk= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id A80674505A; Sat, 18 Jul 2026 01:03:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55F261F000E9; Sat, 18 Jul 2026 01:03:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784336600; bh=Q6G9ezbIlMVkU6BcAV6AfIPu4SPtlwXOdQ5VEzE5oyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MtgFufK82hKi0p92Oz2iEIH0bsV2mt+tfaM0nxTrX+TUBsz6ayYift2JGtxF8C/f8 l+CcrMJavpvyJvF3GWP4kiCLpWjjdytTSAV312rky/ber7d+dTjHMn45onaD1Orn9E 2e8H3Yb2Zm8u7wkMZDwwojymk5sfzCVRwKp/YtKAa96bhk6W9Dbb9m5lMEwd1805MH pOpaGdmNfG246HUO6aANfY19rHMQo8/bol4sguYMcAgxSX13BhrhhN4OOVfwyQa02t 1GE0MBCV4ZdlZdg8IxMKADAkgB8Rd1JZTK8tItUpad4aPBE/njWrmLGo+uIzEYdBYp R5qMY1JrsxXpw== From: SJ Park To: SJ Park Cc: stable@vger.kernel.org, Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH] mm/damon/core: handle region split failure in apply_min_nr_regions() Date: Fri, 17 Jul 2026 18:03:12 -0700 Message-ID: <20260718010312.90397-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260718004301.88883-1-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D8EC340009 X-Stat-Signature: 3bmhuihmwdag4mbiqfty54u1nk6ihp3o X-Rspam-User: X-HE-Tag: 1784336601-679127 X-HE-Meta: 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 jh0KQjl+ 3PwFSBQpX3TjQHvVZGWxYnDeCvH8wcuuuIuNdA+CC4cTGriPK1xIsB6wlAkM/Y/+Bx89J4RAxA6kgD6XRfIsxconaSCVSvcdMu9CRzFldGdwIRJrzN98uGrg1Oy/7K3JKiYoukLXfs0kz/uiknizn2k9Di8LAscsBwUyPHM95amjBI1AGT2vKFXY5rXEBt+/QPEr4hSrdfRx8UQ6+zMQUXkUFix/5ajPegqU5UYVmMu4iED+CLjWXQkiDZ3r3Ezd32h6KTTtPx2O5527bTGeHIjaWAw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 17 Jul 2026 17:43:00 -0700 SJ Park wrote: > damon_apply_min_nr_regions() repeatedly split each region until its size > becomes small enough to meet the user-defined low limit of the number of > regions. The loop assumes the split operation (damon_split_region_at()) > will always succeed and create the new region. But the operation could > silently fail for memory allocation failures, for example. If such > failure happens and the region was the last region, the linked > list-based next region fetching returns invalid pointer. As a result, > invalid memory dereference and corruption could happen. Fix by breaking > the loop in the corner case. Sashiko found no blocker for this series. Sashiko sent findings to damon@ mailing list [1], and I replied to all the comments. Please read those for details. [1] https://lore.kernel.org/damon/ Thanks, SJ [...]