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author | Chris Bainbridge <chris.bainbridge@gmail.com> | 2016-04-25 13:48:38 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-28 12:40:46 -0700 |
commit | feb26ac31a2a5cb88d86680d9a94916a6343e9e6 (patch) | |
tree | aa6b222fdf730e07e6e7f0f4d77684d859213ed7 /drivers/usb | |
parent | edc8c54bf454e6ba4f4631db1603f2297e4d4b67 (diff) | |
download | linux-feb26ac31a2a5cb88d86680d9a94916a6343e9e6.tar.gz linux-feb26ac31a2a5cb88d86680d9a94916a6343e9e6.tar.bz2 linux-feb26ac31a2a5cb88d86680d9a94916a6343e9e6.zip |
usb: core: hub: hub_port_init lock controller instead of bus
The XHCI controller presents two USB buses to the system - one for USB2
and one for USB3. The hub init code (hub_port_init) is reentrant but
only locks one bus per thread, leading to a race condition failure when
two threads attempt to simultaneously initialise a USB2 and USB3 device:
[ 8.034843] xhci_hcd 0000:00:14.0: Timeout while waiting for setup device command
[ 13.183701] usb 3-3: device descriptor read/all, error -110
On a test system this failure occurred on 6% of all boots.
The call traces at the point of failure are:
Call Trace:
[<ffffffff81b9bab7>] schedule+0x37/0x90
[<ffffffff817da7cd>] usb_kill_urb+0x8d/0xd0
[<ffffffff8111e5e0>] ? wake_up_atomic_t+0x30/0x30
[<ffffffff817dafbe>] usb_start_wait_urb+0xbe/0x150
[<ffffffff817db10c>] usb_control_msg+0xbc/0xf0
[<ffffffff817d07de>] hub_port_init+0x51e/0xb70
[<ffffffff817d4697>] hub_event+0x817/0x1570
[<ffffffff810f3e6f>] process_one_work+0x1ff/0x620
[<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620
[<ffffffff810f4684>] worker_thread+0x64/0x4b0
[<ffffffff810f4620>] ? rescuer_thread+0x390/0x390
[<ffffffff810fa7f5>] kthread+0x105/0x120
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
[<ffffffff81ba183f>] ret_from_fork+0x3f/0x70
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
Call Trace:
[<ffffffff817fd36d>] xhci_setup_device+0x53d/0xa40
[<ffffffff817fd87e>] xhci_address_device+0xe/0x10
[<ffffffff817d047f>] hub_port_init+0x1bf/0xb70
[<ffffffff811247ed>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff817d4697>] hub_event+0x817/0x1570
[<ffffffff810f3e6f>] process_one_work+0x1ff/0x620
[<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620
[<ffffffff810f4684>] worker_thread+0x64/0x4b0
[<ffffffff810f4620>] ? rescuer_thread+0x390/0x390
[<ffffffff810fa7f5>] kthread+0x105/0x120
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
[<ffffffff81ba183f>] ret_from_fork+0x3f/0x70
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
Which results from the two call chains:
hub_port_init
usb_get_device_descriptor
usb_get_descriptor
usb_control_msg
usb_internal_control_msg
usb_start_wait_urb
usb_submit_urb / wait_for_completion_timeout / usb_kill_urb
hub_port_init
hub_set_address
xhci_address_device
xhci_setup_device
Mathias Nyman explains the current behaviour violates the XHCI spec:
hub_port_reset() will end up moving the corresponding xhci device slot
to default state.
As hub_port_reset() is called several times in hub_port_init() it
sounds reasonable that we could end up with two threads having their
xhci device slots in default state at the same time, which according to
xhci 4.5.3 specs still is a big no no:
"Note: Software shall not transition more than one Device Slot to the
Default State at a time"
So both threads fail at their next task after this.
One fails to read the descriptor, and the other fails addressing the
device.
Fix this in hub_port_init by locking the USB controller (instead of an
individual bus) to prevent simultaneous initialisation of both buses.
Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel")
Link: https://lkml.org/lkml/2016/2/8/312
Link: https://lkml.org/lkml/2016/2/4/748
Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
-rw-r--r-- | drivers/usb/core/hcd.c | 15 | ||||
-rw-r--r-- | drivers/usb/core/hub.c | 8 |
2 files changed, 17 insertions, 6 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 2ca2cef7f681..980fc5774151 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -994,7 +994,7 @@ static void usb_bus_init (struct usb_bus *bus) bus->bandwidth_allocated = 0; bus->bandwidth_int_reqs = 0; bus->bandwidth_isoc_reqs = 0; - mutex_init(&bus->usb_address0_mutex); + mutex_init(&bus->devnum_next_mutex); } /*-------------------------------------------------------------------------*/ @@ -2521,6 +2521,14 @@ struct usb_hcd *usb_create_shared_hcd(const struct hc_driver *driver, return NULL; } if (primary_hcd == NULL) { + hcd->address0_mutex = kmalloc(sizeof(*hcd->address0_mutex), + GFP_KERNEL); + if (!hcd->address0_mutex) { + kfree(hcd); + dev_dbg(dev, "hcd address0 mutex alloc failed\n"); + return NULL; + } + mutex_init(hcd->address0_mutex); hcd->bandwidth_mutex = kmalloc(sizeof(*hcd->bandwidth_mutex), GFP_KERNEL); if (!hcd->bandwidth_mutex) { @@ -2532,6 +2540,7 @@ struct usb_hcd *usb_create_shared_hcd(const struct hc_driver *driver, dev_set_drvdata(dev, hcd); } else { mutex_lock(&usb_port_peer_mutex); + hcd->address0_mutex = primary_hcd->address0_mutex; hcd->bandwidth_mutex = primary_hcd->bandwidth_mutex; hcd->primary_hcd = primary_hcd; primary_hcd->primary_hcd = primary_hcd; @@ -2598,8 +2607,10 @@ static void hcd_release(struct kref *kref) struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref); mutex_lock(&usb_port_peer_mutex); - if (usb_hcd_is_primary_hcd(hcd)) + if (usb_hcd_is_primary_hcd(hcd)) { + kfree(hcd->address0_mutex); kfree(hcd->bandwidth_mutex); + } if (hcd->shared_hcd) { struct usb_hcd *peer = hcd->shared_hcd; diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index c2270d8fac12..bee13517676f 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2082,7 +2082,7 @@ static void choose_devnum(struct usb_device *udev) struct usb_bus *bus = udev->bus; /* be safe when more hub events are proceed in parallel */ - mutex_lock(&bus->usb_address0_mutex); + mutex_lock(&bus->devnum_next_mutex); if (udev->wusb) { devnum = udev->portnum + 1; BUG_ON(test_bit(devnum, bus->devmap.devicemap)); @@ -2100,7 +2100,7 @@ static void choose_devnum(struct usb_device *udev) set_bit(devnum, bus->devmap.devicemap); udev->devnum = devnum; } - mutex_unlock(&bus->usb_address0_mutex); + mutex_unlock(&bus->devnum_next_mutex); } static void release_devnum(struct usb_device *udev) @@ -4366,7 +4366,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, if (oldspeed == USB_SPEED_LOW) delay = HUB_LONG_RESET_TIME; - mutex_lock(&hdev->bus->usb_address0_mutex); + mutex_lock(hcd->address0_mutex); /* Reset the device; full speed may morph to high speed */ /* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */ @@ -4652,7 +4652,7 @@ fail: hub_port_disable(hub, port1, 0); update_devnum(udev, devnum); /* for disconnect processing */ } - mutex_unlock(&hdev->bus->usb_address0_mutex); + mutex_unlock(hcd->address0_mutex); return retval; } |