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authorMathias Nyman <mathias.nyman@linux.intel.com>2015-08-03 16:07:48 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-16 20:51:47 -0700
commit093ac893e2055e18c0ba494aaeb4910616088eee (patch)
treee3b21910824037685b7bb6da4356d914e4fddf10 /drivers
parentf9b73c1ec1c9bb925c22a094ec26656d99e640ff (diff)
xhci: fix off by one error in TRB DMA address boundary check
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 Miƛkiewicz <arekm@maven.pl> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/host/xhci-ring.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index bcc43a21fd12..a365e9769fcc 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -86,7 +86,7 @@ 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));
}