From nobody Wed Feb 11 16:45:55 2026 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 11EAF1D63E1; Thu, 29 May 2025 15:54:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748534076; cv=none; b=qo+DvGKhfZSeqsNllxsCI8DEs6uIykyNkC41iKRZIQQ1Vdze4BRg0nz0iexDU0BbDwJ8cRifK9gvRUhiDgUDLDtdYN/Z7XWuZnV/dNKl36URTIOm+N4OHo8Ig6ITayA3WPj8ta/11HAInzDqqISMoSXpSCbA8cCFfIdXtymW/+g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748534076; c=relaxed/simple; bh=V3vdyo294X6HZHyo+P4eH0ne8uWxNvjrycKY+kB7wFg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=eLytnPCNP1rd5TVwDlGHOIIWOcvC9NXwe3w6QUFtXUTIcfAbgBijRx24kcgvCkN+qX4BVX+4EXv3YHU4z52wz/IA5KkDzp4UZ+wsl8JGDJQVRm2sTn6kvNdIQt+x+9m9Glmag5KgyHhyM58B4z3ZLi+hvynd6nCw68yD9pKAyuw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4b7WCF22d5zKHMmr; Thu, 29 May 2025 23:54:33 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.252]) by mail.maildlp.com (Postfix) with ESMTP id AE8E11A0F7A; Thu, 29 May 2025 23:54:31 +0800 (CST) Received: from ultra.huawei.com (unknown [10.90.53.71]) by APP3 (Coremail) with SMTP id _Ch0CgBX98EzgzhooMK5Ng--.57784S4; Thu, 29 May 2025 23:54:31 +0800 (CST) From: Pu Lehui To: mhiramat@kernel.org, oleg@redhat.com, peterz@infradead.org, akpm@linux-foundation.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, vbabka@suse.cz, jannh@google.com, pfalcato@suse.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, pulehui@huawei.com Subject: [PATCH v1 2/4] mm: Expose abnormal new_pte during move_ptes Date: Thu, 29 May 2025 15:56:48 +0000 Message-Id: <20250529155650.4017699-3-pulehui@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250529155650.4017699-1-pulehui@huaweicloud.com> References: <20250529155650.4017699-1-pulehui@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _Ch0CgBX98EzgzhooMK5Ng--.57784S4 X-Coremail-Antispam: 1UD129KBjvdXoW7Wr43Kry8tF13uF47ZFy5Arb_yoWfJrXE9r 4Fqryrtr4DAF1vyw15Cwn8urZIkw1q9r10qFnxtr92kw4kJan3ur929rWkZ39ruryq9rW5 XrWktrWSgr1UKjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbDAYFVCjjxCrM7AC8VAFwI0_Wr0E3s1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l82xGYIkIc2x26280x7IE14v26r15M2 8IrcIa0xkI8VCY1x0267AKxVW5JVCq3wA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK 021l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r 4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx 0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWU JVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxV WUtVW8ZwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E 14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIx kGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAF wI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r 4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07UCZXrU UUUU= X-CM-SenderInfo: psxovxtxl6x35dzhxuhorxvhhfrp/ Content-Type: text/plain; charset="utf-8" From: Pu Lehui When executing move_ptes, the new_pte must be NULL, otherwise it will be overwritten by the old_pte, and cause the abnormal new_pte to be leaked. In order to make this problem to be more explicit, let's add WARN_ON_ONCE when new_pte is not NULL. Suggested-by: Oleg Nesterov Signed-off-by: Pu Lehui Reviewed-by: Lorenzo Stoakes --- mm/mremap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/mremap.c b/mm/mremap.c index 83e359754961..4e2491f8c2ce 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -237,6 +237,8 @@ static int move_ptes(struct pagetable_move_control *pmc, =20 for (; old_addr < old_end; old_pte++, old_addr +=3D PAGE_SIZE, new_pte++, new_addr +=3D PAGE_SIZE) { + WARN_ON_ONCE(!pte_none(*new_pte)); + if (pte_none(ptep_get(old_pte))) continue; =20 --=20 2.34.1