<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/usb/core, branch v4.9.331</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>USB: core: Fix RST error in hub.c</title>
<updated>2022-09-28T08:55:45+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2022-09-01T14:36:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=175403641f7227ad5d995df4ed086b3505123ec6'/>
<id>175403641f7227ad5d995df4ed086b3505123ec6</id>
<content type='text'>
commit 766a96dc558385be735a370db867e302c8f22153 upstream.

A recent commit added an invalid RST expression to a kerneldoc comment
in hub.c.  The fix is trivial.

Fixes: 9c6d778800b9 ("USB: core: Prevent nested device-reset calls")
Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Reviewed-by: Bagas Sanjaya &lt;bagasdotme@gmail.com&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/YxDDcsLtRZ7c20pq@rowland.harvard.edu
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 766a96dc558385be735a370db867e302c8f22153 upstream.

A recent commit added an invalid RST expression to a kerneldoc comment
in hub.c.  The fix is trivial.

Fixes: 9c6d778800b9 ("USB: core: Prevent nested device-reset calls")
Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Reviewed-by: Bagas Sanjaya &lt;bagasdotme@gmail.com&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/YxDDcsLtRZ7c20pq@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Prevent nested device-reset calls</title>
<updated>2022-09-15T10:39:45+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2022-08-26T19:31:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d90419b8b8322b6924f6da9da952647f2dadc21b'/>
<id>d90419b8b8322b6924f6da9da952647f2dadc21b</id>
<content type='text'>
commit 9c6d778800b921bde3bff3cff5003d1650f942d1 upstream.

Automatic kernel fuzzing revealed a recursive locking violation in
usb-storage:

============================================
WARNING: possible recursive locking detected
5.18.0 #3 Not tainted
--------------------------------------------
kworker/1:3/1205 is trying to acquire lock:
ffff888018638db8 (&amp;us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230

but task is already holding lock:
ffff888018638db8 (&amp;us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230

...

stack backtrace:
CPU: 1 PID: 1205 Comm: kworker/1:3 Not tainted 5.18.0 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: usb_hub_wq hub_event
Call Trace:
&lt;TASK&gt;
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2988 [inline]
check_deadlock kernel/locking/lockdep.c:3031 [inline]
validate_chain kernel/locking/lockdep.c:3816 [inline]
__lock_acquire.cold+0x152/0x3ca kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x520 kernel/locking/lockdep.c:5630
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x14f/0x1610 kernel/locking/mutex.c:747
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
usb_reset_device+0x37d/0x9a0 drivers/usb/core/hub.c:6109
r871xu_dev_remove+0x21a/0x270 drivers/staging/rtl8712/usb_intf.c:622
usb_unbind_interface+0x1bd/0x890 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:545 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:537
__device_release_driver drivers/base/dd.c:1222 [inline]
device_release_driver_internal+0x1a7/0x2f0 drivers/base/dd.c:1248
usb_driver_release_interface+0x102/0x180 drivers/usb/core/driver.c:627
usb_forced_unbind_intf+0x4d/0xa0 drivers/usb/core/driver.c:1118
usb_reset_device+0x39b/0x9a0 drivers/usb/core/hub.c:6114

This turned out not to be an error in usb-storage but rather a nested
device reset attempt.  That is, as the rtl8712 driver was being
unbound from a composite device in preparation for an unrelated USB
reset (that driver does not have pre_reset or post_reset callbacks),
its -&gt;remove routine called usb_reset_device() -- thus nesting one
reset call within another.

Performing a reset as part of disconnect processing is a questionable
practice at best.  However, the bug report points out that the USB
core does not have any protection against nested resets.  Adding a
reset_in_progress flag and testing it will prevent such errors in the
future.

Link: https://lore.kernel.org/all/CAB7eexKUpvX-JNiLzhXBDWgfg2T9e9_0Tw4HQ6keN==voRbP0g@mail.gmail.com/
Cc: stable@vger.kernel.org
Reported-and-tested-by: Rondreis &lt;linhaoguo86@gmail.com&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/YwkflDxvg0KWqyZK@rowland.harvard.edu
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 9c6d778800b921bde3bff3cff5003d1650f942d1 upstream.

Automatic kernel fuzzing revealed a recursive locking violation in
usb-storage:

============================================
WARNING: possible recursive locking detected
5.18.0 #3 Not tainted
--------------------------------------------
kworker/1:3/1205 is trying to acquire lock:
ffff888018638db8 (&amp;us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230

but task is already holding lock:
ffff888018638db8 (&amp;us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230

...

stack backtrace:
CPU: 1 PID: 1205 Comm: kworker/1:3 Not tainted 5.18.0 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: usb_hub_wq hub_event
Call Trace:
&lt;TASK&gt;
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2988 [inline]
check_deadlock kernel/locking/lockdep.c:3031 [inline]
validate_chain kernel/locking/lockdep.c:3816 [inline]
__lock_acquire.cold+0x152/0x3ca kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x520 kernel/locking/lockdep.c:5630
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x14f/0x1610 kernel/locking/mutex.c:747
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
usb_reset_device+0x37d/0x9a0 drivers/usb/core/hub.c:6109
r871xu_dev_remove+0x21a/0x270 drivers/staging/rtl8712/usb_intf.c:622
usb_unbind_interface+0x1bd/0x890 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:545 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:537
__device_release_driver drivers/base/dd.c:1222 [inline]
device_release_driver_internal+0x1a7/0x2f0 drivers/base/dd.c:1248
usb_driver_release_interface+0x102/0x180 drivers/usb/core/driver.c:627
usb_forced_unbind_intf+0x4d/0xa0 drivers/usb/core/driver.c:1118
usb_reset_device+0x39b/0x9a0 drivers/usb/core/hub.c:6114

This turned out not to be an error in usb-storage but rather a nested
device reset attempt.  That is, as the rtl8712 driver was being
unbound from a composite device in preparation for an unrelated USB
reset (that driver does not have pre_reset or post_reset callbacks),
its -&gt;remove routine called usb_reset_device() -- thus nesting one
reset call within another.

Performing a reset as part of disconnect processing is a questionable
practice at best.  However, the bug report points out that the USB
core does not have any protection against nested resets.  Adding a
reset_in_progress flag and testing it will prevent such errors in the
future.

Link: https://lore.kernel.org/all/CAB7eexKUpvX-JNiLzhXBDWgfg2T9e9_0Tw4HQ6keN==voRbP0g@mail.gmail.com/
Cc: stable@vger.kernel.org
Reported-and-tested-by: Rondreis &lt;linhaoguo86@gmail.com&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/YwkflDxvg0KWqyZK@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: HCD: Fix URB giveback issue in tasklet function</title>
<updated>2022-08-25T09:09:25+00:00</updated>
<author>
<name>Weitao Wang</name>
<email>WeitaoWang-oc@zhaoxin.com</email>
</author>
<published>2022-07-26T07:49:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=77057007feeeefa649d6c5d4d5889fe276cdcc21'/>
<id>77057007feeeefa649d6c5d4d5889fe276cdcc21</id>
<content type='text'>
commit 26c6c2f8a907c9e3a2f24990552a4d77235791e6 upstream.

Usb core introduce the mechanism of giveback of URB in tasklet context to
reduce hardware interrupt handling time. On some test situation(such as
FIO with 4KB block size), when tasklet callback function called to
giveback URB, interrupt handler add URB node to the bh-&gt;head list also.
If check bh-&gt;head list again after finish all URB giveback of local_list,
then it may introduce a "dynamic balance" between giveback URB and add URB
to bh-&gt;head list. This tasklet callback function may not exit for a long
time, which will cause other tasklet function calls to be delayed. Some
real-time applications(such as KB and Mouse) will see noticeable lag.

In order to prevent the tasklet function from occupying the cpu for a long
time at a time, new URBS will not be added to the local_list even though
the bh-&gt;head list is not empty. But also need to ensure the left URB
giveback to be processed in time, so add a member high_prio for structure
giveback_urb_bh to prioritize tasklet and schelule this tasklet again if
bh-&gt;head list is not empty.

At the same time, we are able to prioritize tasklet through structure
member high_prio. So, replace the local high_prio_bh variable with this
structure member in usb_hcd_giveback_urb.

Fixes: 94dfd7edfd5c ("USB: HCD: support giveback of URB in tasklet context")
Cc: stable &lt;stable@kernel.org&gt;
Reviewed-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Weitao Wang &lt;WeitaoWang-oc@zhaoxin.com&gt;
Link: https://lore.kernel.org/r/20220726074918.5114-1-WeitaoWang-oc@zhaoxin.com
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 26c6c2f8a907c9e3a2f24990552a4d77235791e6 upstream.

Usb core introduce the mechanism of giveback of URB in tasklet context to
reduce hardware interrupt handling time. On some test situation(such as
FIO with 4KB block size), when tasklet callback function called to
giveback URB, interrupt handler add URB node to the bh-&gt;head list also.
If check bh-&gt;head list again after finish all URB giveback of local_list,
then it may introduce a "dynamic balance" between giveback URB and add URB
to bh-&gt;head list. This tasklet callback function may not exit for a long
time, which will cause other tasklet function calls to be delayed. Some
real-time applications(such as KB and Mouse) will see noticeable lag.

In order to prevent the tasklet function from occupying the cpu for a long
time at a time, new URBS will not be added to the local_list even though
the bh-&gt;head list is not empty. But also need to ensure the left URB
giveback to be processed in time, so add a member high_prio for structure
giveback_urb_bh to prioritize tasklet and schelule this tasklet again if
bh-&gt;head list is not empty.

At the same time, we are able to prioritize tasklet through structure
member high_prio. So, replace the local high_prio_bh variable with this
structure member in usb_hcd_giveback_urb.

Fixes: 94dfd7edfd5c ("USB: HCD: support giveback of URB in tasklet context")
Cc: stable &lt;stable@kernel.org&gt;
Reviewed-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Weitao Wang &lt;WeitaoWang-oc@zhaoxin.com&gt;
Link: https://lore.kernel.org/r/20220726074918.5114-1-WeitaoWang-oc@zhaoxin.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: hcd-pci: Fully suspend across freeze/thaw cycle</title>
<updated>2022-06-14T14:52:40+00:00</updated>
<author>
<name>Evan Green</name>
<email>evgreen@chromium.org</email>
</author>
<published>2022-04-21T17:39:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6cade0a0b76f116ea0733dc62251376cf9d14984'/>
<id>6cade0a0b76f116ea0733dc62251376cf9d14984</id>
<content type='text'>
[ Upstream commit 63acaa8e9c65dc34dc249440216f8e977f5d2748 ]

The documentation for the freeze() method says that it "should quiesce
the device so that it doesn't generate IRQs or DMA". The unspoken
consequence of not doing this is that MSIs aimed at non-boot CPUs may
get fully lost if they're sent during the period where the target CPU is
offline.

The current callbacks for USB HCD do not fully quiesce interrupts,
specifically on XHCI. Change to use the full suspend/resume flow for
freeze/thaw to ensure interrupts are fully quiesced. This fixes issues
where USB devices fail to thaw during hibernation because XHCI misses
its interrupt and cannot recover.

Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Evan Green &lt;evgreen@chromium.org&gt;
Link: https://lore.kernel.org/r/20220421103751.v3.2.I8226c7fdae88329ef70957b96a39b346c69a914e@changeid
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 63acaa8e9c65dc34dc249440216f8e977f5d2748 ]

The documentation for the freeze() method says that it "should quiesce
the device so that it doesn't generate IRQs or DMA". The unspoken
consequence of not doing this is that MSIs aimed at non-boot CPUs may
get fully lost if they're sent during the period where the target CPU is
offline.

The current callbacks for USB HCD do not fully quiesce interrupts,
specifically on XHCI. Change to use the full suspend/resume flow for
freeze/thaw to ensure interrupts are fully quiesced. This fixes issues
where USB devices fail to thaw during hibernation because XHCI misses
its interrupt and cannot recover.

Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Evan Green &lt;evgreen@chromium.org&gt;
Link: https://lore.kernel.org/r/20220421103751.v3.2.I8226c7fdae88329ef70957b96a39b346c69a914e@changeid
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: new quirk for Dell Gen 2 devices</title>
<updated>2022-06-14T14:52:28+00:00</updated>
<author>
<name>Monish Kumar R</name>
<email>monish.kumar.r@intel.com</email>
</author>
<published>2022-05-20T13:00:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f5c5f3671e40cb70a56a9ede3a3f0afae4f0ace1'/>
<id>f5c5f3671e40cb70a56a9ede3a3f0afae4f0ace1</id>
<content type='text'>
commit 97fa5887cf283bb75ffff5f6b2c0e71794c02400 upstream.

Add USB_QUIRK_NO_LPM and USB_QUIRK_RESET_RESUME quirks for Dell usb gen
2 device to not fail during enumeration.

Found this bug on own testing

Signed-off-by: Monish Kumar R &lt;monish.kumar.r@intel.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20220520130044.17303-1-monish.kumar.r@intel.com
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 97fa5887cf283bb75ffff5f6b2c0e71794c02400 upstream.

Add USB_QUIRK_NO_LPM and USB_QUIRK_RESET_RESUME quirks for Dell usb gen
2 device to not fail during enumeration.

Found this bug on own testing

Signed-off-by: Monish Kumar R &lt;monish.kumar.r@intel.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20220520130044.17303-1-monish.kumar.r@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: quirks: add STRING quirk for VCOM device</title>
<updated>2022-05-12T10:14:53+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2022-04-14T12:31:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=620d89406398169ca9cd4c3e4f3086b2faf22a28'/>
<id>620d89406398169ca9cd4c3e4f3086b2faf22a28</id>
<content type='text'>
commit ec547af8a9ea6441864bad34172676b5652ceb96 upstream.

This has been reported to stall if queried

Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Link: https://lore.kernel.org/r/20220414123152.1700-1-oneukum@suse.com
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 ec547af8a9ea6441864bad34172676b5652ceb96 upstream.

This has been reported to stall if queried

Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Link: https://lore.kernel.org/r/20220414123152.1700-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: quirks: add a Realtek card reader</title>
<updated>2022-05-12T10:14:53+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2022-04-14T11:02:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d5a6f364182100ae29368ebb9cc38f84cf92c663'/>
<id>d5a6f364182100ae29368ebb9cc38f84cf92c663</id>
<content type='text'>
commit 2a7ccf6bb6f147f64c025ad68f4255d8e1e0ce6d upstream.

This device is reported to stall when enummerated.

Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Link: https://lore.kernel.org/r/20220414110209.30924-1-oneukum@suse.com
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 2a7ccf6bb6f147f64c025ad68f4255d8e1e0ce6d upstream.

This device is reported to stall when enummerated.

Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Link: https://lore.kernel.org/r/20220414110209.30924-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Fix hang in usb_kill_urb by adding memory barriers</title>
<updated>2022-02-08T17:15:27+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2022-01-24T20:23:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b50f5ca60475710bbc9a3af32fbfc17b1e69c2f0'/>
<id>b50f5ca60475710bbc9a3af32fbfc17b1e69c2f0</id>
<content type='text'>
commit 26fbe9772b8c459687930511444ce443011f86bf upstream.

The syzbot fuzzer has identified a bug in which processes hang waiting
for usb_kill_urb() to return.  It turns out the issue is not unlinking
the URB; that works just fine.  Rather, the problem arises when the
wakeup notification that the URB has completed is not received.

The reason is memory-access ordering on SMP systems.  In outline form,
usb_kill_urb() and __usb_hcd_giveback_urb() operating concurrently on
different CPUs perform the following actions:

CPU 0					CPU 1
----------------------------		---------------------------------
usb_kill_urb():				__usb_hcd_giveback_urb():
  ...					  ...
  atomic_inc(&amp;urb-&gt;reject);		  atomic_dec(&amp;urb-&gt;use_count);
  ...					  ...
  wait_event(usb_kill_urb_queue,
	atomic_read(&amp;urb-&gt;use_count) == 0);
					  if (atomic_read(&amp;urb-&gt;reject))
						wake_up(&amp;usb_kill_urb_queue);

Confining your attention to urb-&gt;reject and urb-&gt;use_count, you can
see that the overall pattern of accesses on CPU 0 is:

	write urb-&gt;reject, then read urb-&gt;use_count;

whereas the overall pattern of accesses on CPU 1 is:

	write urb-&gt;use_count, then read urb-&gt;reject.

This pattern is referred to in memory-model circles as SB (for "Store
Buffering"), and it is well known that without suitable enforcement of
the desired order of accesses -- in the form of memory barriers -- it
is entirely possible for one or both CPUs to execute their reads ahead
of their writes.  The end result will be that sometimes CPU 0 sees the
old un-decremented value of urb-&gt;use_count while CPU 1 sees the old
un-incremented value of urb-&gt;reject.  Consequently CPU 0 ends up on
the wait queue and never gets woken up, leading to the observed hang
in usb_kill_urb().

The same pattern of accesses occurs in usb_poison_urb() and the
failure pathway of usb_hcd_submit_urb().

The problem is fixed by adding suitable memory barriers.  To provide
proper memory-access ordering in the SB pattern, a full barrier is
required on both CPUs.  The atomic_inc() and atomic_dec() accesses
themselves don't provide any memory ordering, but since they are
present, we can use the optimized smp_mb__after_atomic() memory
barrier in the various routines to obtain the desired effect.

This patch adds the necessary memory barriers.

CC: &lt;stable@vger.kernel.org&gt;
Reported-and-tested-by: syzbot+76629376e06e2c2ad626@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/Ye8K0QYee0Q0Nna2@rowland.harvard.edu
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 26fbe9772b8c459687930511444ce443011f86bf upstream.

The syzbot fuzzer has identified a bug in which processes hang waiting
for usb_kill_urb() to return.  It turns out the issue is not unlinking
the URB; that works just fine.  Rather, the problem arises when the
wakeup notification that the URB has completed is not received.

The reason is memory-access ordering on SMP systems.  In outline form,
usb_kill_urb() and __usb_hcd_giveback_urb() operating concurrently on
different CPUs perform the following actions:

CPU 0					CPU 1
----------------------------		---------------------------------
usb_kill_urb():				__usb_hcd_giveback_urb():
  ...					  ...
  atomic_inc(&amp;urb-&gt;reject);		  atomic_dec(&amp;urb-&gt;use_count);
  ...					  ...
  wait_event(usb_kill_urb_queue,
	atomic_read(&amp;urb-&gt;use_count) == 0);
					  if (atomic_read(&amp;urb-&gt;reject))
						wake_up(&amp;usb_kill_urb_queue);

Confining your attention to urb-&gt;reject and urb-&gt;use_count, you can
see that the overall pattern of accesses on CPU 0 is:

	write urb-&gt;reject, then read urb-&gt;use_count;

whereas the overall pattern of accesses on CPU 1 is:

	write urb-&gt;use_count, then read urb-&gt;reject.

This pattern is referred to in memory-model circles as SB (for "Store
Buffering"), and it is well known that without suitable enforcement of
the desired order of accesses -- in the form of memory barriers -- it
is entirely possible for one or both CPUs to execute their reads ahead
of their writes.  The end result will be that sometimes CPU 0 sees the
old un-decremented value of urb-&gt;use_count while CPU 1 sees the old
un-incremented value of urb-&gt;reject.  Consequently CPU 0 ends up on
the wait queue and never gets woken up, leading to the observed hang
in usb_kill_urb().

The same pattern of accesses occurs in usb_poison_urb() and the
failure pathway of usb_hcd_submit_urb().

The problem is fixed by adding suitable memory barriers.  To provide
proper memory-access ordering in the SB pattern, a full barrier is
required on both CPUs.  The atomic_inc() and atomic_dec() accesses
themselves don't provide any memory ordering, but since they are
present, we can use the optimized smp_mb__after_atomic() memory
barrier in the various routines to obtain the desired effect.

This patch adds the necessary memory barriers.

CC: &lt;stable@vger.kernel.org&gt;
Reported-and-tested-by: syzbot+76629376e06e2c2ad626@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/Ye8K0QYee0Q0Nna2@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: hub: Add delay for SuperSpeed hub resume to let links transit to U0</title>
<updated>2022-01-27T07:47:37+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2021-12-15T12:01:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=55f4ebf52a45360ebf06e41866c0ae75fc2effcb'/>
<id>55f4ebf52a45360ebf06e41866c0ae75fc2effcb</id>
<content type='text'>
[ Upstream commit 00558586382891540c59c9febc671062425a6e47 ]

When a new USB device gets plugged to nested hubs, the affected hub,
which connects to usb 2-1.4-port2, doesn't report there's any change,
hence the nested hubs go back to runtime suspend like nothing happened:
[  281.032951] usb usb2: usb wakeup-resume
[  281.032959] usb usb2: usb auto-resume
[  281.032974] hub 2-0:1.0: hub_resume
[  281.033011] usb usb2-port1: status 0263 change 0000
[  281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.049797] usb 2-1: usb wakeup-resume
[  281.069800] usb 2-1: Waited 0ms for CONNECT
[  281.069810] usb 2-1: finish resume
[  281.070026] hub 2-1:1.0: hub_resume
[  281.070250] usb 2-1-port4: status 0203 change 0000
[  281.070272] usb usb2-port1: resume, status 0
[  281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[  281.089813] usb 2-1.4: usb wakeup-resume
[  281.109792] usb 2-1.4: Waited 0ms for CONNECT
[  281.109801] usb 2-1.4: finish resume
[  281.109991] hub 2-1.4:1.0: hub_resume
[  281.110147] usb 2-1.4-port2: status 0263 change 0000
[  281.110234] usb 2-1-port4: resume, status 0
[  281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[  281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.110426] hub 2-1.4:1.0: hub_suspend
[  281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
[  281.130998] hub 2-1:1.0: hub_suspend
[  281.137788] usb 2-1: usb auto-suspend, wakeup 1
[  281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.177828] usb 2-1: usb wakeup-resume
[  281.197839] usb 2-1: Waited 0ms for CONNECT
[  281.197850] usb 2-1: finish resume
[  281.197984] hub 2-1:1.0: hub_resume
[  281.198203] usb 2-1-port4: status 0203 change 0000
[  281.198228] usb usb2-port1: resume, status 0
[  281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[  281.217835] usb 2-1.4: usb wakeup-resume
[  281.237834] usb 2-1.4: Waited 0ms for CONNECT
[  281.237845] usb 2-1.4: finish resume
[  281.237990] hub 2-1.4:1.0: hub_resume
[  281.238067] usb 2-1.4-port2: status 0263 change 0000
[  281.238148] usb 2-1-port4: resume, status 0
[  281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[  281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.238385] hub 2-1.4:1.0: hub_suspend
[  281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
[  281.258076] hub 2-1:1.0: hub_suspend
[  281.265744] usb 2-1: usb auto-suspend, wakeup 1
[  281.285976] hub 2-0:1.0: hub_suspend
[  281.285988] usb usb2: bus auto-suspend, wakeup 1

USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
the link is in a non-U0 state, then the device must transition the link
to U0 prior to sending the remote wake message", but the hub only
transits the link to U0 after signaling remote wakeup.

So be more forgiving and use a 20ms delay to let the link transit to U0
for remote wakeup.

Suggested-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Link: https://lore.kernel.org/r/20211215120108.336597-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 00558586382891540c59c9febc671062425a6e47 ]

When a new USB device gets plugged to nested hubs, the affected hub,
which connects to usb 2-1.4-port2, doesn't report there's any change,
hence the nested hubs go back to runtime suspend like nothing happened:
[  281.032951] usb usb2: usb wakeup-resume
[  281.032959] usb usb2: usb auto-resume
[  281.032974] hub 2-0:1.0: hub_resume
[  281.033011] usb usb2-port1: status 0263 change 0000
[  281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.049797] usb 2-1: usb wakeup-resume
[  281.069800] usb 2-1: Waited 0ms for CONNECT
[  281.069810] usb 2-1: finish resume
[  281.070026] hub 2-1:1.0: hub_resume
[  281.070250] usb 2-1-port4: status 0203 change 0000
[  281.070272] usb usb2-port1: resume, status 0
[  281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[  281.089813] usb 2-1.4: usb wakeup-resume
[  281.109792] usb 2-1.4: Waited 0ms for CONNECT
[  281.109801] usb 2-1.4: finish resume
[  281.109991] hub 2-1.4:1.0: hub_resume
[  281.110147] usb 2-1.4-port2: status 0263 change 0000
[  281.110234] usb 2-1-port4: resume, status 0
[  281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[  281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.110426] hub 2-1.4:1.0: hub_suspend
[  281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
[  281.130998] hub 2-1:1.0: hub_suspend
[  281.137788] usb 2-1: usb auto-suspend, wakeup 1
[  281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.177828] usb 2-1: usb wakeup-resume
[  281.197839] usb 2-1: Waited 0ms for CONNECT
[  281.197850] usb 2-1: finish resume
[  281.197984] hub 2-1:1.0: hub_resume
[  281.198203] usb 2-1-port4: status 0203 change 0000
[  281.198228] usb usb2-port1: resume, status 0
[  281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[  281.217835] usb 2-1.4: usb wakeup-resume
[  281.237834] usb 2-1.4: Waited 0ms for CONNECT
[  281.237845] usb 2-1.4: finish resume
[  281.237990] hub 2-1.4:1.0: hub_resume
[  281.238067] usb 2-1.4-port2: status 0263 change 0000
[  281.238148] usb 2-1-port4: resume, status 0
[  281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[  281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[  281.238385] hub 2-1.4:1.0: hub_suspend
[  281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
[  281.258076] hub 2-1:1.0: hub_suspend
[  281.265744] usb 2-1: usb auto-suspend, wakeup 1
[  281.285976] hub 2-0:1.0: hub_suspend
[  281.285988] usb usb2: bus auto-suspend, wakeup 1

USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
the link is in a non-U0 state, then the device must transition the link
to U0 prior to sending the remote wake message", but the hub only
transits the link to U0 after signaling remote wakeup.

So be more forgiving and use a 20ms delay to let the link transit to U0
for remote wakeup.

Suggested-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Link: https://lore.kernel.org/r/20211215120108.336597-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Fix "slab-out-of-bounds Write" bug in usb_hcd_poll_rh_status</title>
<updated>2022-01-27T07:47:30+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2022-01-01T02:07:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2e7c5fffc28c128215297b09e427cb51e89f3f46'/>
<id>2e7c5fffc28c128215297b09e427cb51e89f3f46</id>
<content type='text'>
commit 1d7d4c07932e04355d6e6528d44a2f2c9e354346 upstream.

When the USB core code for getting root-hub status reports was
originally written, it was assumed that the hub driver would be its
only caller.  But this isn't true now; user programs can use usbfs to
communicate with root hubs and get status reports.  When they do this,
they may use a transfer_buffer that is smaller than the data returned
by the HCD, which will lead to a buffer overflow error when
usb_hcd_poll_rh_status() tries to store the status data.  This was
discovered by syzbot:

BUG: KASAN: slab-out-of-bounds in memcpy include/linux/fortify-string.h:225 [inline]
BUG: KASAN: slab-out-of-bounds in usb_hcd_poll_rh_status+0x5f4/0x780 drivers/usb/core/hcd.c:776
Write of size 2 at addr ffff88801da403c0 by task syz-executor133/4062

This patch fixes the bug by reducing the amount of status data if it
won't fit in the transfer_buffer.  If some data gets discarded then
the URB's completion status is set to -EOVERFLOW rather than 0, to let
the user know what happened.

Reported-and-tested-by: syzbot+3ae6a2b06f131ab9849f@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/Yc+3UIQJ2STbxNua@rowland.harvard.edu
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 1d7d4c07932e04355d6e6528d44a2f2c9e354346 upstream.

When the USB core code for getting root-hub status reports was
originally written, it was assumed that the hub driver would be its
only caller.  But this isn't true now; user programs can use usbfs to
communicate with root hubs and get status reports.  When they do this,
they may use a transfer_buffer that is smaller than the data returned
by the HCD, which will lead to a buffer overflow error when
usb_hcd_poll_rh_status() tries to store the status data.  This was
discovered by syzbot:

BUG: KASAN: slab-out-of-bounds in memcpy include/linux/fortify-string.h:225 [inline]
BUG: KASAN: slab-out-of-bounds in usb_hcd_poll_rh_status+0x5f4/0x780 drivers/usb/core/hcd.c:776
Write of size 2 at addr ffff88801da403c0 by task syz-executor133/4062

This patch fixes the bug by reducing the amount of status data if it
won't fit in the transfer_buffer.  If some data gets discarded then
the URB's completion status is set to -EOVERFLOW rather than 0, to let
the user know what happened.

Reported-and-tested-by: syzbot+3ae6a2b06f131ab9849f@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/Yc+3UIQJ2STbxNua@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
