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[209.132.180.67]) by mx.google.com with ESMTP id i38si3203428eda.64.2019.10.17.22.05.01; Thu, 17 Oct 2019 22:05:25 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=ODBiqp3O; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404414AbfJPWT1 (ORCPT + 99 others); Wed, 16 Oct 2019 18:19:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:43692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437672AbfJPVyG (ORCPT ); Wed, 16 Oct 2019 17:54:06 -0400 Received: from localhost (unknown [192.55.54.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EEF1821D7A; Wed, 16 Oct 2019 21:54:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571262846; bh=VIgycL42FaxYZvfYvFylTUsM+pW3BJ+crMbYSoZQlCI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ODBiqp3OYXTdHHvhXsKvIkT6tkg071HMDLG6acu2lq7VSj1AxLnk0meDX3YgeMYE7 YrKss/6nyLiaBbsd3BoxQGZB5dm4UdzgpKgO991NJZxKs3VoyHfY+IQq9PKrB7E9zO eZa8pA4tBVd1Twyka9bc81+9wsen6dkh088wlJQE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sebastian Ott , Vasily Gorbik Subject: [PATCH 4.9 04/92] s390/cio: exclude subchannels with no parent from pseudo check Date: Wed, 16 Oct 2019 14:49:37 -0700 Message-Id: <20191016214802.403126375@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214759.600329427@linuxfoundation.org> References: <20191016214759.600329427@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vasily Gorbik commit ab5758848039de9a4b249d46e4ab591197eebaf2 upstream. ccw console is created early in start_kernel and used before css is initialized or ccw console subchannel is registered. Until then console subchannel does not have a parent. For that reason assume subchannels with no parent are not pseudo subchannels. This fixes the following kasan finding: BUG: KASAN: global-out-of-bounds in sch_is_pseudo_sch+0x8e/0x98 Read of size 8 at addr 00000000000005e8 by task swapper/0/0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc8-07370-g6ac43dd12538 #2 Hardware name: IBM 2964 NC9 702 (z/VM 6.4.0) Call Trace: ([<000000000012cd76>] show_stack+0x14e/0x1e0) [<0000000001f7fb44>] dump_stack+0x1a4/0x1f8 [<00000000007d7afc>] print_address_description+0x64/0x3c8 [<00000000007d75f6>] __kasan_report+0x14e/0x180 [<00000000018a2986>] sch_is_pseudo_sch+0x8e/0x98 [<000000000189b950>] cio_enable_subchannel+0x1d0/0x510 [<00000000018cac7c>] ccw_device_recognition+0x12c/0x188 [<0000000002ceb1a8>] ccw_device_enable_console+0x138/0x340 [<0000000002cf1cbe>] con3215_init+0x25e/0x300 [<0000000002c8770a>] console_init+0x68a/0x9b8 [<0000000002c6a3d6>] start_kernel+0x4fe/0x728 [<0000000000100070>] startup_continue+0x70/0xd0 Cc: stable@vger.kernel.org Reviewed-by: Sebastian Ott Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- drivers/s390/cio/css.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -1120,6 +1120,8 @@ device_initcall(cio_settle_init); int sch_is_pseudo_sch(struct subchannel *sch) { + if (!sch->dev.parent) + return 0; return sch == to_css(sch->dev.parent)->pseudo_subchannel; }