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 1817D3D813E; Mon, 4 May 2026 13:04:24 +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=1777899865; cv=none; b=qxsfGB+W3GkjLm94wDe+F2lWq7ESS0gRfmEoS1h0kPXBksyTopetL4m2TynsF7w2POl4/xPviFTgGi1YVnL8LgPLu0Yp70t/UqwWKXXli1vp2OinlxkykU6WhpmLjtmV7uNycipVDM4SgzPA707sETfssV0GaaXAKx0so9DyZGA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777899865; c=relaxed/simple; bh=Pshoy4gNUESr72jkg51Vu4NZDeQVG+b2J7eBZyXJXa8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QfY6ne1hUVpf4jV8Z48kP0h2iMaPZtmklb65NMigscmmd5D2cTpf7yID3kS2ZKvAvCpjxbdp6rnqBulmlgeY6W7f4mq2//A5AT6RolXgCtSY4pdoRq+gRe1KNpxIIB/IQBFGkdHW4O7BAfY1U4WvN+U1FOd/cw0TsMzlDtQadIk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D2GwhBsi; 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="D2GwhBsi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 217A0C2BCB8; Mon, 4 May 2026 13:04:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777899864; bh=Pshoy4gNUESr72jkg51Vu4NZDeQVG+b2J7eBZyXJXa8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D2GwhBsipAdkdlfWAqbcXteC6g/ScRV0F7UWOdaq15Fx5dbmShsi3K6793xOzEhI9 4LXrX3pqZOU3NsU208sR9zqfpMZSXxAFlUz/Rw1QTyZK/S9Wgsc+uILdBjWYJSmQ7V fncSm0OnKPAWnCyxYZNVcSixcfPBC+hYDT/sLkmn3NxdtV75vvJdj/1tFi/LMnJReZ ZvoA9ytaVFmaOfTy5LrWMcTIZJTvYjKYa8MBp+rRECdYW3oWQOTDx+gWK5ojMMae4J 1KjiBvqIjjPmHoUCGOPLNJWAyNdlOknrt46VLe8SqGAUQ4jr1BlobE+50pBcxrYQ5n BGDQLgXnGZpGA== From: SeongJae Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, SeongJae Park , Andrew Morton Subject: [PATCH 6.18.y] mm/damon/core: disallow non-power of two min_region_sz on damon_start() Date: Mon, 4 May 2026 06:04:18 -0700 Message-ID: <20260504130418.26862-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026050357-senator-aroma-1859@gregkh> References: <2026050357-senator-aroma-1859@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Commit d8f867fa0825 ("mm/damon: add damon_ctx->min_sz_region") introduced a bug that allows unaligned DAMON region address ranges. Commit c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") fixed it, but only for damon_commit_ctx() use case. Still, DAMON sysfs interface can emit non-power of two min_region_sz via damon_start(). Fix the path by adding the is_power_of_2() check on damon_start(). The issue was discovered by sashiko [1]. Link: https://lore.kernel.org/20260411213638.77768-1-sj@kernel.org Link: https://lore.kernel.org/20260403155530.64647-1-sj@kernel.org [1] Fixes: d8f867fa0825 ("mm/damon: add damon_ctx->min_sz_region") Signed-off-by: SeongJae Park Cc: # 6.18.x Signed-off-by: Andrew Morton (cherry picked from commit 95093e5cb4c5b50a5b1a4b79f2942b62744bd66a) Signed-off-by: SeongJae Park --- mm/damon/core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index 87b6c9c2d647..e016ca7fde5e 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1352,6 +1352,11 @@ int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive) int i; int err = 0; + for (i = 0; i < nr_ctxs; i++) { + if (!is_power_of_2(ctxs[i]->min_sz_region)) + return -EINVAL; + } + mutex_lock(&damon_lock); if ((exclusive && nr_running_ctxs) || (!exclusive && running_exclusive_ctxs)) { -- 2.47.3