<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/usb/host, branch v3.0.52</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>xhci: Fix potential NULL ptr deref in command cancellation.</title>
<updated>2012-10-31T16:51:36+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2012-10-16T20:17:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=713b9c260ba25938606ab794a1dfc438c727eb2c'/>
<id>713b9c260ba25938606ab794a1dfc438c727eb2c</id>
<content type='text'>
commit 43a09f7fb01fa1e091416a2aa49b6c666458c1ee upstream.

The command cancellation code doesn't check whether find_trb_seg()
couldn't find the segment that contains the TRB to be canceled.  This
could cause a NULL pointer deference later in the function when next_trb
is called.  It's unlikely to happen unless something is wrong with the
command ring pointers, so add some debugging in case it happens.

This patch should be backported to stable kernels as old as 3.0, that
contain the commit b63f4053cc8aa22a98e3f9a97845afe6c15d0a0d "xHCI:
handle command after aborting the command ring".

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 43a09f7fb01fa1e091416a2aa49b6c666458c1ee upstream.

The command cancellation code doesn't check whether find_trb_seg()
couldn't find the segment that contains the TRB to be canceled.  This
could cause a NULL pointer deference later in the function when next_trb
is called.  It's unlikely to happen unless something is wrong with the
command ring pointers, so add some debugging in case it happens.

This patch should be backported to stable kernels as old as 3.0, that
contain the commit b63f4053cc8aa22a98e3f9a97845afe6c15d0a0d "xHCI:
handle command after aborting the command ring".

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ehci: Add yet-another Lucid nohandoff pci quirk</title>
<updated>2012-10-31T16:51:35+00:00</updated>
<author>
<name>Anisse Astier</name>
<email>anisse@astier.eu</email>
</author>
<published>2012-10-09T10:22:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=299697673bce44a4af03faa31abf1266c160b459'/>
<id>299697673bce44a4af03faa31abf1266c160b459</id>
<content type='text'>
commit 8daf8b6086f9d575200cd0aa3797e26137255609 upstream.

Board name changed on another shipping Lucid tablet.

Signed-off-by: Anisse Astier &lt;anisse@astier.eu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8daf8b6086f9d575200cd0aa3797e26137255609 upstream.

Board name changed on another shipping Lucid tablet.

Signed-off-by: Anisse Astier &lt;anisse@astier.eu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ehci: fix Lucid nohandoff pci quirk to be more generic with BIOS versions</title>
<updated>2012-10-31T16:51:35+00:00</updated>
<author>
<name>Anisse Astier</name>
<email>anisse@astier.eu</email>
</author>
<published>2012-10-09T10:22:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3f89e7a23865b5a4de6175097dc9e6162d875cff'/>
<id>3f89e7a23865b5a4de6175097dc9e6162d875cff</id>
<content type='text'>
commit c323dc023b9501e5d09582ec7efd1d40a9001d99 upstream.

BIOS vendors keep changing the BIOS versions. Only match the beginning
of the string to match all Lucid tablets with board name M11JB.

Signed-off-by: Anisse Astier &lt;anisse@astier.eu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c323dc023b9501e5d09582ec7efd1d40a9001d99 upstream.

BIOS vendors keep changing the BIOS versions. Only match the beginning
of the string to match all Lucid tablets with board name M11JB.

Signed-off-by: Anisse Astier &lt;anisse@astier.eu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xHCI: handle command after aborting the command ring</title>
<updated>2012-10-28T17:02:14+00:00</updated>
<author>
<name>Elric Fu</name>
<email>elricfu1@gmail.com</email>
</author>
<published>2012-06-27T08:55:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=29b3f4e6bcede9f46132ea1dd52592a9a80a6849'/>
<id>29b3f4e6bcede9f46132ea1dd52592a9a80a6849</id>
<content type='text'>
commit b63f4053cc8aa22a98e3f9a97845afe6c15d0a0d upstream.

According to xHCI spec section 4.6.1.1 and section 4.6.1.2,
after aborting a command on the command ring, xHC will
generate a command completion event with its completion
code set to Command Ring Stopped at least. If a command is
currently executing at the time of aborting a command, xHC
also generate a command completion event with its completion
code set to Command Abort. When the command ring is stopped,
software may remove, add, or rearrage Command Descriptors.

To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci. When the command ring is stopped,
software will find the command trbs described by command
descriptors in cancel_cmd_list and modify it to No Op
command. If software can't find the matched trbs, we can
think it had been finished.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Note from Sarah: The TRB_TYPE_LINK_LE32 macro is not in the 3.0 stable
kernel, so I added it to this patch.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;


</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b63f4053cc8aa22a98e3f9a97845afe6c15d0a0d upstream.

According to xHCI spec section 4.6.1.1 and section 4.6.1.2,
after aborting a command on the command ring, xHC will
generate a command completion event with its completion
code set to Command Ring Stopped at least. If a command is
currently executing at the time of aborting a command, xHC
also generate a command completion event with its completion
code set to Command Abort. When the command ring is stopped,
software may remove, add, or rearrage Command Descriptors.

To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci. When the command ring is stopped,
software will find the command trbs described by command
descriptors in cancel_cmd_list and modify it to No Op
command. If software can't find the matched trbs, we can
think it had been finished.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Note from Sarah: The TRB_TYPE_LINK_LE32 macro is not in the 3.0 stable
kernel, so I added it to this patch.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;


</pre>
</div>
</content>
</entry>
<entry>
<title>xHCI: cancel command after command timeout</title>
<updated>2012-10-28T17:02:14+00:00</updated>
<author>
<name>Elric Fu</name>
<email>elricfu1@gmail.com</email>
</author>
<published>2012-06-27T08:31:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4b360f4937e646f777a3049c65124056c84c6977'/>
<id>4b360f4937e646f777a3049c65124056c84c6977</id>
<content type='text'>
commit 6e4468b9a0793dfb53eb80d9fe52c739b13b27fd upstream.

The patch is used to cancel command when the command isn't
acknowledged and a timeout occurs.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6e4468b9a0793dfb53eb80d9fe52c739b13b27fd upstream.

The patch is used to cancel command when the command isn't
acknowledged and a timeout occurs.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xHCI: add aborting command ring function</title>
<updated>2012-10-28T17:02:14+00:00</updated>
<author>
<name>Elric Fu</name>
<email>elricfu1@gmail.com</email>
</author>
<published>2012-06-27T08:31:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bc47204b268516ae4085ebdc81a34ddda71b77c4'/>
<id>bc47204b268516ae4085ebdc81a34ddda71b77c4</id>
<content type='text'>
commit b92cc66c047ff7cf587b318fe377061a353c120f upstream.

Software have to abort command ring and cancel command
when a command is failed or hang. Otherwise, the command
ring will hang up and can't handle the others. An example
of a command that may hang is the Address Device Command,
because waiting for a SET_ADDRESS request to be acknowledged
by a USB device is outside of the xHC's ability to control.

To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci.

Sarah: Fixed missing newline on "Have the command ring been stopped?"
debugging statement.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b92cc66c047ff7cf587b318fe377061a353c120f upstream.

Software have to abort command ring and cancel command
when a command is failed or hang. Otherwise, the command
ring will hang up and can't handle the others. An example
of a command that may hang is the Address Device Command,
because waiting for a SET_ADDRESS request to be acknowledged
by a USB device is outside of the xHC's ability to control.

To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci.

Sarah: Fixed missing newline on "Have the command ring been stopped?"
debugging statement.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xHCI: add cmd_ring_state</title>
<updated>2012-10-28T17:02:13+00:00</updated>
<author>
<name>Elric Fu</name>
<email>elricfu1@gmail.com</email>
</author>
<published>2012-06-27T08:30:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c76e4de05c23fea3d6ad6df63876a9397dd7c85a'/>
<id>c76e4de05c23fea3d6ad6df63876a9397dd7c85a</id>
<content type='text'>
commit c181bc5b5d5c79b71203cd10cef97f802fb6f9c1 upstream.

Adding cmd_ring_state for command ring. It helps to verify
the current command ring state for controlling the command
ring operations.

This patch should be backported to kernels as old as 3.0.  The commit
7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an assertion to
check for virt_dev=0 bug." papers over the NULL pointer dereference that
I now believe is related to a timed out Set Address command.  This (and
the four patches that follow it) contain the real fix that also allows
VIA USB 3.0 hubs to consistently re-enumerate during the plug/unplug
stress tests.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c181bc5b5d5c79b71203cd10cef97f802fb6f9c1 upstream.

Adding cmd_ring_state for command ring. It helps to verify
the current command ring state for controlling the command
ring operations.

This patch should be backported to kernels as old as 3.0.  The commit
7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an assertion to
check for virt_dev=0 bug." papers over the NULL pointer dereference that
I now believe is related to a timed out Set Address command.  This (and
the four patches that follow it) contain the real fix that also allows
VIA USB 3.0 hubs to consistently re-enumerate during the plug/unplug
stress tests.

Signed-off-by: Elric Fu &lt;elricfu1@gmail.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: Miroslav Sabljic &lt;miroslav.sabljic@avl.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Increase XHCI suspend timeout to 16ms</title>
<updated>2012-10-07T15:27:26+00:00</updated>
<author>
<name>Michael Spang</name>
<email>spang@chromium.org</email>
</author>
<published>2012-09-14T17:05:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a4e92d29a86daf9609c875eccb1357657f2ac93f'/>
<id>a4e92d29a86daf9609c875eccb1357657f2ac93f</id>
<content type='text'>
commit a6e097dfdfd189b6929af6efa1d289af61858386 upstream.

The Intel XHCI specification says that after clearing the run/stop bit
the controller may take up to 16ms to halt. We've seen a device take
14ms, which with the current timeout of 10ms causes the kernel to
abort the suspend. Increasing the timeout to the recommended value
fixes the problem.

This patch should be backported to kernels as old as 2.6.37, that
contain the commit 5535b1d5f8885695c6ded783c692e3c0d0eda8ca "USB: xHCI:
PCI power management implementation".

Signed-off-by: Michael Spang &lt;spang@chromium.org&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a6e097dfdfd189b6929af6efa1d289af61858386 upstream.

The Intel XHCI specification says that after clearing the run/stop bit
the controller may take up to 16ms to halt. We've seen a device take
14ms, which with the current timeout of 10ms causes the kernel to
abort the suspend. Increasing the timeout to the recommended value
fixes the problem.

This patch should be backported to kernels as old as 2.6.37, that
contain the commit 5535b1d5f8885695c6ded783c692e3c0d0eda8ca "USB: xHCI:
PCI power management implementation".

Signed-off-by: Michael Spang &lt;spang@chromium.org&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xhci: Intel Panther Point BEI quirk.</title>
<updated>2012-10-07T15:27:25+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2012-09-19T23:27:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9c1ce83c1250a3ad4c2d131d59295561b09efe83'/>
<id>9c1ce83c1250a3ad4c2d131d59295561b09efe83</id>
<content type='text'>
commit 80fab3b244a22e0ca539d2439bdda50e81e5666f upstream.

When a device with an isochronous endpoint is behind a hub plugged into
the Intel Panther Point xHCI host controller, and the driver submits
multiple frames per URB, the xHCI driver will set the Block Event
Interrupt (BEI) flag on all but the last TD for the URB.  This causes
the host controller to place an event on the event ring, but not send an
interrupt.  When the last TD for the URB completes, BEI is cleared, and
we get an interrupt for the whole URB.

However, under a Panther Point xHCI host controller, if the parent hub
is unplugged when one or more events from transfers with BEI set are on
the event ring, a port status change event is placed on the event ring,
but no interrupt is generated.  This means URBs stop completing, and the
USB device disconnect is not noticed.  Something like a USB headset will
cause mplayer to hang when the device is disconnected.

If another transfer is sent (such as running `sudo lsusb -v`), the next
transfer event seems to "unstick" the event ring, the xHCI driver gets
an interrupt, and the disconnect is reported to the USB core.

The fix is not to use the BEI flag under the Panther Point xHCI host.
This will impact power consumption and system responsiveness, because
the xHCI driver will receive an interrupt for every frame in all
isochronous URBs instead of once per URB.

Intel chipset developers confirm that this bug will be hit if the BEI
flag is used on any endpoint, not just ones that are behind a hub.

This patch should be backported to kernels as old as 3.0, that contain
the commit 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support
EHCI/xHCI port switching."

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 80fab3b244a22e0ca539d2439bdda50e81e5666f upstream.

When a device with an isochronous endpoint is behind a hub plugged into
the Intel Panther Point xHCI host controller, and the driver submits
multiple frames per URB, the xHCI driver will set the Block Event
Interrupt (BEI) flag on all but the last TD for the URB.  This causes
the host controller to place an event on the event ring, but not send an
interrupt.  When the last TD for the URB completes, BEI is cleared, and
we get an interrupt for the whole URB.

However, under a Panther Point xHCI host controller, if the parent hub
is unplugged when one or more events from transfers with BEI set are on
the event ring, a port status change event is placed on the event ring,
but no interrupt is generated.  This means URBs stop completing, and the
USB device disconnect is not noticed.  Something like a USB headset will
cause mplayer to hang when the device is disconnected.

If another transfer is sent (such as running `sudo lsusb -v`), the next
transfer event seems to "unstick" the event ring, the xHCI driver gets
an interrupt, and the disconnect is reported to the USB core.

The fix is not to use the BEI flag under the Panther Point xHCI host.
This will impact power consumption and system responsiveness, because
the xHCI driver will receive an interrupt for every frame in all
isochronous URBs instead of once per URB.

Intel chipset developers confirm that this bug will be hit if the BEI
flag is used on any endpoint, not just ones that are behind a hub.

This patch should be backported to kernels as old as 3.0, that contain
the commit 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support
EHCI/xHCI port switching."

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xhci: Fix bug after deq ptr set to link TRB.</title>
<updated>2012-10-02T16:47:39+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2012-07-26T19:03:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e3439be1c0b9df0ca9b760ff4861be5d6145da26'/>
<id>e3439be1c0b9df0ca9b760ff4861be5d6145da26</id>
<content type='text'>
commit 50d0206fcaea3e736f912fd5b00ec6233fb4ce44 upstream.

This patch fixes a particularly nasty bug that was revealed by the ring
expansion patches.  The bug has been present since the very beginning of
the xHCI driver history, and could have caused general protection faults
from bad memory accesses.

The first thing to note is that a Set TR Dequeue Pointer command can
move the dequeue pointer to a link TRB, if the canceled or stalled
transfer TD ended just before a link TRB.  The function to increment the
dequeue pointer, inc_deq, was written before cancellation and stall
support was added.  It assumed that the dequeue pointer could never
point to a link TRB.  It would unconditionally increment the dequeue
pointer at the start of the function, check if the pointer was now on a
link TRB, and move it to the top of the next segment if so.

This means that if a Set TR Dequeue Point command moved the dequeue
pointer to a link TRB, a subsequent call to inc_deq() would move the
pointer off the segment and into la-la-land.  It would then read from
that memory to determine if it was a link TRB.  Other functions would
often call inc_deq() until the dequeue pointer matched some other
pointer, which means this function would quite happily read all of
system memory before wrapping around to the right pointer value.

Often, there would be another endpoint segment from a different ring
allocated from the same DMA pool, which would be contiguous to the
segment inc_deq just stepped off of.  inc_deq would eventually find the
link TRB in that segment, and blindly move the dequeue pointer back to
the top of the correct ring segment.

The only reason the original code worked at all is because there was
only one ring segment.  With the ring expansion patches, the dequeue
pointer would eventually wrap into place, but the dequeue segment would
be out-of-sync.  On the second TD after the dequeue pointer was moved to
a link TRB, trb_in_td() would fail (because the dequeue pointer and
dequeue segment were out-of-sync), and this message would appear:

ERROR Transfer event TRB DMA ptr not part of current TD

This fixes bugzilla entry 4333 (option-based modem unhappy on USB 3.0
port: "Transfer event TRB DMA ptr not part of current TD", "rejecting
I/O to offline device"),

	https://bugzilla.kernel.org/show_bug.cgi?id=43333

and possibly other general protection fault bugs as well.

This patch should be backported to kernels as old as 2.6.31.  A separate
patch will be created for kernels older than 3.4, since inc_deq was
modified in 3.4 and this patch will not apply.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: James Ettle &lt;theholyettlz@googlemail.com&gt;
Tested-by: Matthew Hall &lt;mhall@mhcomputing.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 50d0206fcaea3e736f912fd5b00ec6233fb4ce44 upstream.

This patch fixes a particularly nasty bug that was revealed by the ring
expansion patches.  The bug has been present since the very beginning of
the xHCI driver history, and could have caused general protection faults
from bad memory accesses.

The first thing to note is that a Set TR Dequeue Pointer command can
move the dequeue pointer to a link TRB, if the canceled or stalled
transfer TD ended just before a link TRB.  The function to increment the
dequeue pointer, inc_deq, was written before cancellation and stall
support was added.  It assumed that the dequeue pointer could never
point to a link TRB.  It would unconditionally increment the dequeue
pointer at the start of the function, check if the pointer was now on a
link TRB, and move it to the top of the next segment if so.

This means that if a Set TR Dequeue Point command moved the dequeue
pointer to a link TRB, a subsequent call to inc_deq() would move the
pointer off the segment and into la-la-land.  It would then read from
that memory to determine if it was a link TRB.  Other functions would
often call inc_deq() until the dequeue pointer matched some other
pointer, which means this function would quite happily read all of
system memory before wrapping around to the right pointer value.

Often, there would be another endpoint segment from a different ring
allocated from the same DMA pool, which would be contiguous to the
segment inc_deq just stepped off of.  inc_deq would eventually find the
link TRB in that segment, and blindly move the dequeue pointer back to
the top of the correct ring segment.

The only reason the original code worked at all is because there was
only one ring segment.  With the ring expansion patches, the dequeue
pointer would eventually wrap into place, but the dequeue segment would
be out-of-sync.  On the second TD after the dequeue pointer was moved to
a link TRB, trb_in_td() would fail (because the dequeue pointer and
dequeue segment were out-of-sync), and this message would appear:

ERROR Transfer event TRB DMA ptr not part of current TD

This fixes bugzilla entry 4333 (option-based modem unhappy on USB 3.0
port: "Transfer event TRB DMA ptr not part of current TD", "rejecting
I/O to offline device"),

	https://bugzilla.kernel.org/show_bug.cgi?id=43333

and possibly other general protection fault bugs as well.

This patch should be backported to kernels as old as 2.6.31.  A separate
patch will be created for kernels older than 3.4, since inc_deq was
modified in 3.4 and this patch will not apply.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Tested-by: James Ettle &lt;theholyettlz@googlemail.com&gt;
Tested-by: Matthew Hall &lt;mhall@mhcomputing.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
