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| author | Chris Bainbridge <chris.bainbridge@gmail.com> | 2015-05-19 16:30:51 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-05-24 09:23:28 -0700 |
| commit | a00918d0521df1c7a2ec9143142a3ea998c8526d (patch) | |
| tree | a1a467fb29397ac72250da249b3db1ff21a85ac4 /drivers/usb/host/xhci.h | |
| parent | b04c846ceaad42f9e37f3626c7e8f457603863f0 (diff) | |
| download | linux-a00918d0521df1c7a2ec9143142a3ea998c8526d.tar.bz2 | |
usb: host: xhci: add mutex for non-thread-safe data
Regression in commit 638139eb95d2 ("usb: hub: allow to process more usb
hub events in parallel")
The regression resulted in intermittent failure to initialise a 10-port
hub (with three internal VL812 4-port hub controllers) on boot, with a
failure rate of around 8%, due to multiple race conditions when
accessing addr_dev and slot_id in struct xhci_hcd.
This regression also exposed a problem with xhci_setup_device, which
"should be protected by the usb_address0_mutex" but no longer is due to
commit 6fecd4f2a58c ("USB: separate usb_address0 mutexes for each bus")
With separate buses (and locks) it is no longer the case that a single
lock will protect xhci_setup_device from accesses by two parallel
threads processing events on the two buses.
Fix this by adding a mutex to protect addr_dev and slot_id in struct
xhci_hcd, and by making the assignment of slot_id atomic.
Fixes multiple boot errors:
[ 0.583008] xhci_hcd 0000:00:14.0: Bad Slot ID 2
[ 0.583009] xhci_hcd 0000:00:14.0: Could not allocate xHCI USB device data structures
[ 0.583012] usb usb1-port3: couldn't allocate usb_device
And:
[ 0.637409] xhci_hcd 0000:00:14.0: Error while assigning device slot ID
[ 0.637417] xhci_hcd 0000:00:14.0: Max number of devices this xHCI host supports is 32.
[ 0.637421] usb usb1-port1: couldn't allocate usb_device
And:
[ 0.753372] xhci_hcd 0000:00:14.0: ERROR: unexpected setup context command completion code 0x0.
[ 0.753373] usb 1-3: hub failed to enable device, error -22
[ 0.753400] xhci_hcd 0000:00:14.0: Error while assigning device slot ID
[ 0.753402] xhci_hcd 0000:00:14.0: Max number of devices this xHCI host supports is 32.
[ 0.753403] usb usb1-port3: couldn't allocate usb_device
And:
[ 11.018386] usb 1-3: device descriptor read/all, error -110
And:
[ 5.753838] xhci_hcd 0000:00:14.0: Timeout while waiting for setup device command
Tested with 200 reboots, resulting in no USB hub init related errors.
Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel")
Link: https://lkml.kernel.org/g/CAP-bSRb=A0iEYobdGCLpwynS7pkxpt_9ZnwyZTPVAoy0Y=Zo3Q@mail.gmail.com
Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Cc: <stable@vger.kernel.org> # 3.18+
[changed git commit description style for checkpatch -Mathias]
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci.h')
| -rw-r--r-- | drivers/usb/host/xhci.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index ea75e8ccd3c1..6977f8491fa7 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1497,6 +1497,8 @@ struct xhci_hcd { struct list_head lpm_failed_devs; /* slot enabling and address device helpers */ + /* these are not thread safe so use mutex */ + struct mutex mutex; struct completion addr_dev; int slot_id; /* For USB 3.0 LPM enable/disable. */ |