diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2015-08-03 16:07:48 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-08-16 20:51:47 -0700 |
| commit | 093ac893e2055e18c0ba494aaeb4910616088eee (patch) | |
| tree | e3b21910824037685b7bb6da4356d914e4fddf10 /drivers | |
| parent | f9b73c1ec1c9bb925c22a094ec26656d99e640ff (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 Miśkiewicz <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.c | 2 |
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)); } |