From nobody Tue Feb 10 12:40:41 2026 Received: from canpmsgout08.his.huawei.com (canpmsgout08.his.huawei.com [113.46.200.223]) (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 B2C8F2D5950; Fri, 16 Jan 2026 07:52:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.223 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768549956; cv=none; b=qnUWNV+xJnqtLS5b4ZVvOxI+L6YQws7I/h1rJQo7aeTku7pIoANyS3QX96vvjFqpC5055PDeogXcsA2GGQpn/1dwUX+HUij8WrDIBGK1werD+W1Nu5qA/2WlsShqEgwjsSSyg5cfprvJ5xorKkIj9WNwoDQrIdo9VD8ASgtqiE4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768549956; c=relaxed/simple; bh=u92f1kbTpIdKtEEuVeYvX55xieu/6RBt+ks+eV0Jdcc=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=H+U3U3fLuG1zG7UY42PlTY3rBhqLTHpyjCg+4cpRucVJc7f/i9LwIP1poPbVCTSc8+9mDnYjt0HgV9UdxYcacgBZiQXJiisHZpIansLjnZ9hTvL/Ec1RWCWs9t1aZmyez66t4YK5RdMLDGD095NvkR6yQRqrog1YO5DKrxAnPHo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=lxVLbGGP; arc=none smtp.client-ip=113.46.200.223 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="lxVLbGGP" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=3vxAPAMjiZnbkDd7gTIpK7c4P2xbFpz++FhONFEcjcg=; b=lxVLbGGPAJ1Q2ZkMqwn2Y1+76UEq84emQlyR5k6Tibxp037a6+mhKCE9ZMUIMpZW0/IphQZ/m rkSJ+P5k+TONPtt/biXHy0wmfXqyoMycqT4mZ4EPT3P5aWUrq2uZcuuqyhRf/Lgl5wqIWmWNmjW DeDZ6zJAPAu3uMux3SUeh8c= Received: from mail.maildlp.com (unknown [172.19.163.200]) by canpmsgout08.his.huawei.com (SkyGuard) with ESMTPS id 4dssRx3nFwzmVWy; Fri, 16 Jan 2026 15:49:01 +0800 (CST) Received: from kwepemr500012.china.huawei.com (unknown [7.202.195.23]) by mail.maildlp.com (Postfix) with ESMTPS id DC4684055B; Fri, 16 Jan 2026 15:52:22 +0800 (CST) Received: from localhost.localdomain (10.50.85.180) by kwepemr500012.china.huawei.com (7.202.195.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 16 Jan 2026 15:52:22 +0800 From: Ziming Du To: , , , CC: , , Subject: [PATCH v4 1/4] PCI/sysfs: Prohibit unaligned access to I/O port Date: Fri, 16 Jan 2026 16:17:18 +0800 Message-ID: <20260116081723.1603603-2-duziming2@huawei.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260116081723.1603603-1-duziming2@huawei.com> References: <20260116081723.1603603-1-duziming2@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemr500012.china.huawei.com (7.202.195.23) Unaligned access is harmful for non-x86 archs such as arm64. When we use pwrite or pread to access the I/O port resources with unaligned offset, system will crash as follows: Unable to handle kernel paging request at virtual address fffffbfffe8010c1 Internal error: Oops: 0000000096000061 [#1] SMP Call trace: _outw include/asm-generic/io.h:594 [inline] logic_outw+0x54/0x218 lib/logic_pio.c:305 pci_resource_io drivers/pci/pci-sysfs.c:1157 [inline] pci_write_resource_io drivers/pci/pci-sysfs.c:1191 [inline] pci_write_resource_io+0x208/0x260 drivers/pci/pci-sysfs.c:1181 sysfs_kf_bin_write+0x188/0x210 fs/sysfs/file.c:158 kernfs_fop_write_iter+0x2e8/0x4b0 fs/kernfs/file.c:338 vfs_write+0x7bc/0xac8 fs/read_write.c:586 ksys_write+0x12c/0x270 fs/read_write.c:639 __arm64_sys_write+0x78/0xb8 fs/read_write.c:648 Although x86 might handle unaligned I/O accesses by splitting cycles, this approach is still limited because PCI device registers typically expect natural alignment. A global prohibition of unaligned accesses ensures consistent behavior across all architectures and prevents unexpected hardware side effects. Fixes: 8633328be242 ("PCI: Allow read/write access to sysfs I/O port resour= ces") Signed-off-by: Yongqiang Liu Signed-off-by: Ziming Du Suggested-by: Ilpo J=C3=A4rvinen --- drivers/pci/pci-sysfs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index c2df915ad2d29..18e5d4603b472 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "pci.h" =20 #ifndef ARCH_PCI_DEV_GROUPS @@ -1166,12 +1167,16 @@ static ssize_t pci_resource_io(struct file *filp, s= truct kobject *kobj, *(u8 *)buf =3D inb(port); return 1; case 2: + if (!IS_ALIGNED(port, count)) + return -EINVAL; if (write) outw(*(u16 *)buf, port); else *(u16 *)buf =3D inw(port); return 2; case 4: + if (!IS_ALIGNED(port, count)) + return -EINVAL; if (write) outl(*(u32 *)buf, port); else --=20 2.43.0