From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751988AbbK3BZR (ORCPT ); Sun, 29 Nov 2015 20:25:17 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37794 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751544AbbK3BZO (ORCPT ); Sun, 29 Nov 2015 20:25:14 -0500 Message-Id: <20151129214703.269304855@1wt.eu> User-Agent: quilt/0.63-1 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?ISO-8859-15?q?Arkadiusz=20Mi=C5=9Bkiewicz?= , Mathias Nyman , Greg Kroah-Hartman , Ben Hutchings , Willy Tarreau MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 In-Reply-To: <8acf8256ccc72771a80b7851061027bc@local> Subject: [PATCH 2.6.32 09/38] [PATCH 09/38] xhci: fix off by one error in TRB DMA address boundary check Date: Mon, 30 Nov 2015 01:25:06 +0000 Content-Transfer-Encoding: X-Mailer: Evolution 3.18.2-1 X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ commit 7895086afde2a05fa24a0e410d8e6b75ca7c8fdd upstream. We need to check that a TRB is part of the current segment before calculating its DMA address. Previously a ring segment didn't use a full memory page, and every new ring segment got a new memory page, so the off by one error in checking the upper bound was never seen. Now that we use a full memory page, 256 TRBs (4096 bytes), the off by one didn't catch the case when a TRB was the first element of the next segment. This is triggered if the virtual memory pages for a ring segment are next to each in increasing order where the ring buffer wraps around and causes errors like: [ 106.398223] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 0 comp_code 1 [ 106.398230] xhci_hcd 0000:00:14.0: Looking for event-dma fffd3000 trb-start fffd4fd0 trb-end fffd5000 seg-start fffd4000 seg-end fffd4ff0 The trb-end address is one outside the end-seg address. Tested-by: Arkadiusz Miśkiewicz Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings (cherry picked from commit 6e3ae6256145b5597bee0296eb5fc384cd86aa3d) Signed-off-by: Willy Tarreau --- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 38fb682..fa22638 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -80,7 +80,7 @@ dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg, return 0; /* offset in TRBs */ segment_offset = trb - seg->trbs; - if (segment_offset > TRBS_PER_SEGMENT) + if (segment_offset >= TRBS_PER_SEGMENT) return 0; return seg->dma + (segment_offset * sizeof(*trb)); } -- 1.7.12.2.21.g234cd45.dirty