<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/usb, branch v4.9.56</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Revert "xhci: Limit USB2 port wake support for AMD Promontory hosts"</title>
<updated>2017-10-12T09:51:18+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2017-09-18T14:39:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a13481f8cdca4e3f08d950e230f49742d95fc70c'/>
<id>a13481f8cdca4e3f08d950e230f49742d95fc70c</id>
<content type='text'>
commit bcd6a7aa13800afc1418e6b29d944d882214939a upstream.

This reverts commit dec08194ffeccfa1cf085906b53d301930eae18f.

Commit dec08194ffec ("xhci: Limit USB2 port wake support for AMD Promontory
hosts") makes all high speed USB ports on ASUS PRIME B350M-A cease to
function after enabling runtime PM.

All boards with this chipsets will be affected, so revert the commit.

The original patch was added to stable 4.9, 4.11 and 4.12 and needs
to reverted from there as well

Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Signed-off-by: Mathias Nyman &lt;mathias.nyman@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 bcd6a7aa13800afc1418e6b29d944d882214939a upstream.

This reverts commit dec08194ffeccfa1cf085906b53d301930eae18f.

Commit dec08194ffec ("xhci: Limit USB2 port wake support for AMD Promontory
hosts") makes all high speed USB ports on ASUS PRIME B350M-A cease to
function after enabling runtime PM.

All boards with this chipsets will be affected, so revert the commit.

The original patch was added to stable 4.9, 4.11 and 4.12 and needs
to reverted from there as well

Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Signed-off-by: Mathias Nyman &lt;mathias.nyman@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xhci: set missing SuperSpeedPlus Link Protocol bit in roothub descriptor</title>
<updated>2017-10-12T09:51:18+00:00</updated>
<author>
<name>Mathias Nyman</name>
<email>mathias.nyman@linux.intel.com</email>
</author>
<published>2017-09-18T14:39:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f77615db8ae850ef196843502b1d0aaae8e173d2'/>
<id>f77615db8ae850ef196843502b1d0aaae8e173d2</id>
<content type='text'>
commit 7bea22b124d77845c85a62eaa29a85ba6cc2f899 upstream.

A SuperSpeedPlus roothub needs to have the Link Protocol (LP) bit set in
the bmSublinkSpeedAttr[] entry of a SuperSpeedPlus descriptor.

If the xhci controller has an optional Protocol Speed ID (PSI) table then
that will be used as a base to create the roothub SuperSpeedPlus
descriptor.
The PSI table does not however necessary contain the LP bit so we need
to set it manually.

Check the psi speed and set LP bit if speed is 10Gbps or higher.
We're not setting it for 5 to 10Gbps as USB 3.1 specification always
mention SuperSpeedPlus for 10Gbps or higher, and some SSIC USB 3.0 speeds
can be over 5Gbps, such as SSIC-G3B-L1 at 5830 Mbps

Signed-off-by: Mathias Nyman &lt;mathias.nyman@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 7bea22b124d77845c85a62eaa29a85ba6cc2f899 upstream.

A SuperSpeedPlus roothub needs to have the Link Protocol (LP) bit set in
the bmSublinkSpeedAttr[] entry of a SuperSpeedPlus descriptor.

If the xhci controller has an optional Protocol Speed ID (PSI) table then
that will be used as a base to create the roothub SuperSpeedPlus
descriptor.
The PSI table does not however necessary contain the LP bit so we need
to set it manually.

Check the psi speed and set LP bit if speed is 10Gbps or higher.
We're not setting it for 5 to 10Gbps as USB 3.1 specification always
mention SuperSpeedPlus for 10Gbps or higher, and some SSIC USB 3.0 speeds
can be over 5Gbps, such as SSIC-G3B-L1 at 5830 Mbps

Signed-off-by: Mathias Nyman &lt;mathias.nyman@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xhci: Fix sleeping with spin_lock_irq() held in ASmedia 1042A workaround</title>
<updated>2017-10-12T09:51:18+00:00</updated>
<author>
<name>Mathias Nyman</name>
<email>mathias.nyman@linux.intel.com</email>
</author>
<published>2017-09-18T14:39:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f1a04773d773900cd2f670b18c20c86a4218420f'/>
<id>f1a04773d773900cd2f670b18c20c86a4218420f</id>
<content type='text'>
commit 4ec1cd3eeeee7ccc35681270da028dbc29ca7bbd upstream.

The flow control workaround for ASM1042A xHC hosts sleeps between
register polling. The workaround gets called in several places, among
them with spin_lock_irq() held when xHC host is resumed or hoplug removed.

This was noticed as kernel panics at resume on a Dell XPS15 9550 with
TB16 thunderbolt dock.

Avoid sleeping with spin_lock_irq() held, use udelay() instead

The original workaround was added to 4.9 and 4.12 stable releases,
this patch needs to be applied to those as well.

Fixes: 9da5a1092b13 ("xhci: Bad Ethernet performance plugged in ASM1042A host")
Reported-by: Jose Marino &lt;marinoj@nso.edu&gt;
Tested-by: Jose Marino &lt;marinoj@nso.edu&gt;
Signed-off-by: Mathias Nyman &lt;mathias.nyman@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 4ec1cd3eeeee7ccc35681270da028dbc29ca7bbd upstream.

The flow control workaround for ASM1042A xHC hosts sleeps between
register polling. The workaround gets called in several places, among
them with spin_lock_irq() held when xHC host is resumed or hoplug removed.

This was noticed as kernel panics at resume on a Dell XPS15 9550 with
TB16 thunderbolt dock.

Avoid sleeping with spin_lock_irq() held, use udelay() instead

The original workaround was added to 4.9 and 4.12 stable releases,
this patch needs to be applied to those as well.

Fixes: 9da5a1092b13 ("xhci: Bad Ethernet performance plugged in ASM1042A host")
Reported-by: Jose Marino &lt;marinoj@nso.edu&gt;
Tested-by: Jose Marino &lt;marinoj@nso.edu&gt;
Signed-off-by: Mathias Nyman &lt;mathias.nyman@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xhci: fix finding correct bus_state structure for USB 3.1 hosts</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Mathias Nyman</name>
<email>mathias.nyman@linux.intel.com</email>
</author>
<published>2017-09-18T14:39:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=67e752e1d60f9f40b8391dad48f7c842bdba6ec4'/>
<id>67e752e1d60f9f40b8391dad48f7c842bdba6ec4</id>
<content type='text'>
commit 5a838a13c9b4e5dd188b7a6eaeb894e9358ead0c upstream.

xhci driver keeps a bus_state structure for each hcd (usb2 and usb3)

The structure is picked based on hcd speed, but driver only compared
for HCD_USB3 speed, returning the wrong bus_state for HCD_USB31 hosts.

This caused null pointer dereference errors in bus_resume function.

Signed-off-by: Mathias Nyman &lt;mathias.nyman@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 5a838a13c9b4e5dd188b7a6eaeb894e9358ead0c upstream.

xhci driver keeps a bus_state structure for each hcd (usb2 and usb3)

The structure is picked based on hcd speed, but driver only compared
for HCD_USB3 speed, returning the wrong bus_state for HCD_USB31 hosts.

This caused null pointer dereference errors in bus_resume function.

Signed-off-by: Mathias Nyman &lt;mathias.nyman@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: fix out-of-bounds in usb_set_configuration</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-09-19T13:07:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a6d4ce2e8b653ff7facde0d0051663fa4cf57b78'/>
<id>a6d4ce2e8b653ff7facde0d0051663fa4cf57b78</id>
<content type='text'>
commit bd7a3fe770ebd8391d1c7d072ff88e9e76d063eb upstream.

Andrey Konovalov reported a possible out-of-bounds problem for a USB interface
association descriptor.  He writes:
	It seems there's no proper size check of a USB_DT_INTERFACE_ASSOCIATION
	descriptor. It's only checked that the size is &gt;= 2 in
	usb_parse_configuration(), so find_iad() might do out-of-bounds access
	to intf_assoc-&gt;bInterfaceCount.

And he's right, we don't check for crazy descriptors of this type very well, so
resolve this problem.  Yet another issue found by syzkaller...

Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Tested-by: Andrey Konovalov &lt;andreyknvl@google.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 bd7a3fe770ebd8391d1c7d072ff88e9e76d063eb upstream.

Andrey Konovalov reported a possible out-of-bounds problem for a USB interface
association descriptor.  He writes:
	It seems there's no proper size check of a USB_DT_INTERFACE_ASSOCIATION
	descriptor. It's only checked that the size is &gt;= 2 in
	usb_parse_configuration(), so find_iad() might do out-of-bounds access
	to intf_assoc-&gt;bInterfaceCount.

And he's right, we don't check for crazy descriptors of this type very well, so
resolve this problem.  Yet another issue found by syzkaller...

Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Tested-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>usb: Increase quirk delay for USB devices</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Dmitry Fleytman</name>
<email>dmitry@daynix.com</email>
</author>
<published>2017-09-05T08:40:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=43feb29db4c5233fd77eedd57b4f2a53c9db9eff'/>
<id>43feb29db4c5233fd77eedd57b4f2a53c9db9eff</id>
<content type='text'>
commit b2a542bbb3081dbd64acc8929c140d196664c406 upstream.

Commit e0429362ab15
("usb: Add device quirk for Logitech HD Pro Webcams C920 and C930e")
introduced quirk to workaround an issue with some Logitech webcams.

The workaround is introducing delay for some USB operations.

According to our testing, delay introduced by original commit
is not long enough and in rare cases we still see issues described
by the aforementioned commit.

This patch increases delays introduced by original commit.
Having this patch applied we do not see those problems anymore.

Signed-off-by: Dmitry Fleytman &lt;dmitry@daynix.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 b2a542bbb3081dbd64acc8929c140d196664c406 upstream.

Commit e0429362ab15
("usb: Add device quirk for Logitech HD Pro Webcams C920 and C930e")
introduced quirk to workaround an issue with some Logitech webcams.

The workaround is introducing delay for some USB operations.

According to our testing, delay introduced by original commit
is not long enough and in rare cases we still see issues described
by the aforementioned commit.

This patch increases delays introduced by original commit.
Having this patch applied we do not see those problems anymore.

Signed-off-by: Dmitry Fleytman &lt;dmitry@daynix.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: harden cdc_parse_cdc_header</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-09-21T14:58:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=767f7a2cf33a135fe3f57010b51c3f6e92d7677d'/>
<id>767f7a2cf33a135fe3f57010b51c3f6e92d7677d</id>
<content type='text'>
commit 2e1c42391ff2556387b3cb6308b24f6f65619feb upstream.

Andrey Konovalov reported a possible out-of-bounds problem for the
cdc_parse_cdc_header function.  He writes:
	It looks like cdc_parse_cdc_header() doesn't validate buflen
	before accessing buffer[1], buffer[2] and so on. The only check
	present is while (buflen &gt; 0).

So fix this issue up by properly validating the buffer length matches
what the descriptor says it is.

Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Tested-by: Andrey Konovalov &lt;andreyknvl@google.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 2e1c42391ff2556387b3cb6308b24f6f65619feb upstream.

Andrey Konovalov reported a possible out-of-bounds problem for the
cdc_parse_cdc_header function.  He writes:
	It looks like cdc_parse_cdc_header() doesn't validate buflen
	before accessing buffer[1], buffer[2] and so on. The only check
	present is while (buflen &gt; 0).

So fix this issue up by properly validating the buffer length matches
what the descriptor says it is.

Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Tested-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: uas: fix bug in handling of alternate settings</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2017-09-22T15:56:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d77606e93d819ad4b8f57511ff61a629ced49750'/>
<id>d77606e93d819ad4b8f57511ff61a629ced49750</id>
<content type='text'>
commit 786de92b3cb26012d3d0f00ee37adf14527f35c4 upstream.

The uas driver has a subtle bug in the way it handles alternate
settings.  The uas_find_uas_alt_setting() routine returns an
altsetting value (the bAlternateSetting number in the descriptor), but
uas_use_uas_driver() then treats that value as an index to the
intf-&gt;altsetting array, which it isn't.

Normally this doesn't cause any problems because the various
alternate settings have bAlternateSetting values 0, 1, 2, ..., so the
value is equal to the index in the array.  But this is not guaranteed,
and Andrey Konovalov used the syzkaller fuzzer with KASAN to get a
slab-out-of-bounds error by violating this assumption.

This patch fixes the bug by making uas_find_uas_alt_setting() return a
pointer to the altsetting entry rather than either the value or the
index.  Pointers are less subject to misinterpretation.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Tested-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
CC: Oliver Neukum &lt;oneukum@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&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 786de92b3cb26012d3d0f00ee37adf14527f35c4 upstream.

The uas driver has a subtle bug in the way it handles alternate
settings.  The uas_find_uas_alt_setting() routine returns an
altsetting value (the bAlternateSetting number in the descriptor), but
uas_use_uas_driver() then treats that value as an index to the
intf-&gt;altsetting array, which it isn't.

Normally this doesn't cause any problems because the various
alternate settings have bAlternateSetting values 0, 1, 2, ..., so the
value is equal to the index in the array.  But this is not guaranteed,
and Andrey Konovalov used the syzkaller fuzzer with KASAN to get a
slab-out-of-bounds error by violating this assumption.

This patch fixes the bug by making uas_find_uas_alt_setting() return a
pointer to the altsetting entry rather than either the value or the
index.  Pointers are less subject to misinterpretation.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Tested-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
CC: Oliver Neukum &lt;oneukum@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: g_mass_storage: Fix deadlock when driver is unbound</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2017-09-21T17:22:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=da785bb64fa661f5081b5c0351b798396b6071a6'/>
<id>da785bb64fa661f5081b5c0351b798396b6071a6</id>
<content type='text'>
commit 1fbbb78f25d1291274f320462bf6908906f538db upstream.

As a holdover from the old g_file_storage gadget, the g_mass_storage
legacy gadget driver attempts to unregister itself when its main
operating thread terminates (if it hasn't been unregistered already).
This is not strictly necessary; it was never more than an attempt to
have the gadget fail cleanly if something went wrong and the main
thread was killed.

However, now that the UDC core manages gadget drivers independently of
UDC drivers, this scheme doesn't work any more.  A simple test:

	modprobe dummy-hcd
	modprobe g-mass-storage file=...
	rmmod dummy-hcd

ends up in a deadlock with the following backtrace:

 sysrq: SysRq : Show Blocked State
   task                PC stack   pid father
 file-storage    D    0  1130      2 0x00000000
 Call Trace:
  __schedule+0x53e/0x58c
  schedule+0x6e/0x77
  schedule_preempt_disabled+0xd/0xf
  __mutex_lock.isra.1+0x129/0x224
  ? _raw_spin_unlock_irqrestore+0x12/0x14
  __mutex_lock_slowpath+0x12/0x14
  mutex_lock+0x28/0x2b
  usb_gadget_unregister_driver+0x29/0x9b [udc_core]
  usb_composite_unregister+0x10/0x12 [libcomposite]
  msg_cleanup+0x1d/0x20 [g_mass_storage]
  msg_thread_exits+0xd/0xdd7 [g_mass_storage]
  fsg_main_thread+0x1395/0x13d6 [usb_f_mass_storage]
  ? __schedule+0x573/0x58c
  kthread+0xd9/0xdb
  ? do_set_interface+0x25c/0x25c [usb_f_mass_storage]
  ? init_completion+0x1e/0x1e
  ret_from_fork+0x19/0x24
 rmmod           D    0  1155    683 0x00000000
 Call Trace:
  __schedule+0x53e/0x58c
  schedule+0x6e/0x77
  schedule_timeout+0x26/0xbc
  ? __schedule+0x573/0x58c
  do_wait_for_common+0xb3/0x128
  ? usleep_range+0x81/0x81
  ? wake_up_q+0x3f/0x3f
  wait_for_common+0x2e/0x45
  wait_for_completion+0x17/0x19
  fsg_common_put+0x34/0x81 [usb_f_mass_storage]
  fsg_free_inst+0x13/0x1e [usb_f_mass_storage]
  usb_put_function_instance+0x1a/0x25 [libcomposite]
  msg_unbind+0x2a/0x42 [g_mass_storage]
  __composite_unbind+0x4a/0x6f [libcomposite]
  composite_unbind+0x12/0x14 [libcomposite]
  usb_gadget_remove_driver+0x4f/0x77 [udc_core]
  usb_del_gadget_udc+0x52/0xcc [udc_core]
  dummy_udc_remove+0x27/0x2c [dummy_hcd]
  platform_drv_remove+0x1d/0x31
  device_release_driver_internal+0xe9/0x16d
  device_release_driver+0x11/0x13
  bus_remove_device+0xd2/0xe2
  device_del+0x19f/0x221
  ? selinux_capable+0x22/0x27
  platform_device_del+0x21/0x63
  platform_device_unregister+0x10/0x1a
  cleanup+0x20/0x817 [dummy_hcd]
  SyS_delete_module+0x10c/0x197
  ? ____fput+0xd/0xf
  ? task_work_run+0x55/0x62
  ? prepare_exit_to_usermode+0x65/0x75
  do_fast_syscall_32+0x86/0xc3
  entry_SYSENTER_32+0x4e/0x7c

What happens is that removing the dummy-hcd driver causes the UDC core
to unbind the gadget driver, which it does while holding the udc_lock
mutex.  The unbind routine in g_mass_storage tells the main thread to
exit and waits for it to terminate.

But as mentioned above, when the main thread exits it tries to
unregister the mass-storage function driver.  Via the composite
framework this ends up calling usb_gadget_unregister_driver(), which
tries to acquire the udc_lock mutex.  The result is deadlock.

The simplest way to fix the problem is not to be so clever: The main
thread doesn't have to unregister the function driver.  The side
effects won't be so terrible; if the gadget is still attached to a USB
host when the main thread is killed, it will appear to the host as
though the gadget's firmware has crashed -- a reasonably accurate
interpretation, and an all-too-common occurrence for USB mass-storage
devices.

In fact, the code to unregister the driver when the main thread exits
is specific to g-mass-storage; it is not used when f-mass-storage is
included as a function in a larger composite device.  Therefore the
entire mechanism responsible for this (the fsg_operations structure
with its -&gt;thread_exits method, the fsg_common_set_ops() routine, and
the msg_thread_exits() callback routine) can all be eliminated.  Even
the msg_registered bitflag can be removed, because now the driver is
unregistered in only one place rather than in two places.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Acked-by: Felipe Balbi &lt;felipe.balbi@linux.intel.com&gt;
Acked-by: Michal Nazarewicz &lt;mina86@mina86.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 1fbbb78f25d1291274f320462bf6908906f538db upstream.

As a holdover from the old g_file_storage gadget, the g_mass_storage
legacy gadget driver attempts to unregister itself when its main
operating thread terminates (if it hasn't been unregistered already).
This is not strictly necessary; it was never more than an attempt to
have the gadget fail cleanly if something went wrong and the main
thread was killed.

However, now that the UDC core manages gadget drivers independently of
UDC drivers, this scheme doesn't work any more.  A simple test:

	modprobe dummy-hcd
	modprobe g-mass-storage file=...
	rmmod dummy-hcd

ends up in a deadlock with the following backtrace:

 sysrq: SysRq : Show Blocked State
   task                PC stack   pid father
 file-storage    D    0  1130      2 0x00000000
 Call Trace:
  __schedule+0x53e/0x58c
  schedule+0x6e/0x77
  schedule_preempt_disabled+0xd/0xf
  __mutex_lock.isra.1+0x129/0x224
  ? _raw_spin_unlock_irqrestore+0x12/0x14
  __mutex_lock_slowpath+0x12/0x14
  mutex_lock+0x28/0x2b
  usb_gadget_unregister_driver+0x29/0x9b [udc_core]
  usb_composite_unregister+0x10/0x12 [libcomposite]
  msg_cleanup+0x1d/0x20 [g_mass_storage]
  msg_thread_exits+0xd/0xdd7 [g_mass_storage]
  fsg_main_thread+0x1395/0x13d6 [usb_f_mass_storage]
  ? __schedule+0x573/0x58c
  kthread+0xd9/0xdb
  ? do_set_interface+0x25c/0x25c [usb_f_mass_storage]
  ? init_completion+0x1e/0x1e
  ret_from_fork+0x19/0x24
 rmmod           D    0  1155    683 0x00000000
 Call Trace:
  __schedule+0x53e/0x58c
  schedule+0x6e/0x77
  schedule_timeout+0x26/0xbc
  ? __schedule+0x573/0x58c
  do_wait_for_common+0xb3/0x128
  ? usleep_range+0x81/0x81
  ? wake_up_q+0x3f/0x3f
  wait_for_common+0x2e/0x45
  wait_for_completion+0x17/0x19
  fsg_common_put+0x34/0x81 [usb_f_mass_storage]
  fsg_free_inst+0x13/0x1e [usb_f_mass_storage]
  usb_put_function_instance+0x1a/0x25 [libcomposite]
  msg_unbind+0x2a/0x42 [g_mass_storage]
  __composite_unbind+0x4a/0x6f [libcomposite]
  composite_unbind+0x12/0x14 [libcomposite]
  usb_gadget_remove_driver+0x4f/0x77 [udc_core]
  usb_del_gadget_udc+0x52/0xcc [udc_core]
  dummy_udc_remove+0x27/0x2c [dummy_hcd]
  platform_drv_remove+0x1d/0x31
  device_release_driver_internal+0xe9/0x16d
  device_release_driver+0x11/0x13
  bus_remove_device+0xd2/0xe2
  device_del+0x19f/0x221
  ? selinux_capable+0x22/0x27
  platform_device_del+0x21/0x63
  platform_device_unregister+0x10/0x1a
  cleanup+0x20/0x817 [dummy_hcd]
  SyS_delete_module+0x10c/0x197
  ? ____fput+0xd/0xf
  ? task_work_run+0x55/0x62
  ? prepare_exit_to_usermode+0x65/0x75
  do_fast_syscall_32+0x86/0xc3
  entry_SYSENTER_32+0x4e/0x7c

What happens is that removing the dummy-hcd driver causes the UDC core
to unbind the gadget driver, which it does while holding the udc_lock
mutex.  The unbind routine in g_mass_storage tells the main thread to
exit and waits for it to terminate.

But as mentioned above, when the main thread exits it tries to
unregister the mass-storage function driver.  Via the composite
framework this ends up calling usb_gadget_unregister_driver(), which
tries to acquire the udc_lock mutex.  The result is deadlock.

The simplest way to fix the problem is not to be so clever: The main
thread doesn't have to unregister the function driver.  The side
effects won't be so terrible; if the gadget is still attached to a USB
host when the main thread is killed, it will appear to the host as
though the gadget's firmware has crashed -- a reasonably accurate
interpretation, and an all-too-common occurrence for USB mass-storage
devices.

In fact, the code to unregister the driver when the main thread exits
is specific to g-mass-storage; it is not used when f-mass-storage is
included as a function in a larger composite device.  Therefore the
entire mechanism responsible for this (the fsg_operations structure
with its -&gt;thread_exits method, the fsg_common_set_ops() routine, and
the msg_thread_exits() callback routine) can all be eliminated.  Even
the msg_registered bitflag can be removed, because now the driver is
unregistered in only one place rather than in two places.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Acked-by: Felipe Balbi &lt;felipe.balbi@linux.intel.com&gt;
Acked-by: Michal Nazarewicz &lt;mina86@mina86.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>usb: gadget: mass_storage: set msg_registered after msg registered</title>
<updated>2017-10-12T09:51:17+00:00</updated>
<author>
<name>Li Jun</name>
<email>jun.li@nxp.com</email>
</author>
<published>2017-04-14T11:12:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2b5c7b95ea36521e7cb4f93be546a8be5fd9d667'/>
<id>2b5c7b95ea36521e7cb4f93be546a8be5fd9d667</id>
<content type='text'>
commit 8e55d30322c6a0ef746c256a1beda9c73ecb27a6 upstream.

If there is no UDC available, the msg register will fail and this
flag will not be set, but the driver is already added into pending
driver list, then the module removal modprobe -r can not remove
the driver from the pending list.

Signed-off-by: Li Jun &lt;jun.li@nxp.com&gt;
Signed-off-by: Felipe Balbi &lt;felipe.balbi@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 8e55d30322c6a0ef746c256a1beda9c73ecb27a6 upstream.

If there is no UDC available, the msg register will fail and this
flag will not be set, but the driver is already added into pending
driver list, then the module removal modprobe -r can not remove
the driver from the pending list.

Signed-off-by: Li Jun &lt;jun.li@nxp.com&gt;
Signed-off-by: Felipe Balbi &lt;felipe.balbi@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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