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commit 90a646c770 upstream.
This commit fixes the following oops:
[10238.622067] scsi host3: uas_eh_bus_reset_handler start
[10240.766164] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10245.779365] usb 3-4: device descriptor read/8, error -110
[10245.883331] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10250.897603] usb 3-4: device descriptor read/8, error -110
[10251.058200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
[10251.058244] IP: [<ffffffff815ac6e1>] xhci_check_streams_endpoint+0x91/0x140
<snip>
[10251.059473] Call Trace:
[10251.059487] [<ffffffff815aca6c>] xhci_calculate_streams_and_bitmask+0xbc/0x130
[10251.059520] [<ffffffff815aeb5f>] xhci_alloc_streams+0x10f/0x5a0
[10251.059548] [<ffffffff810a4685>] ? check_preempt_curr+0x75/0xa0
[10251.059575] [<ffffffff810a46dc>] ? ttwu_do_wakeup+0x2c/0x100
[10251.059601] [<ffffffff810a49e6>] ? ttwu_do_activate.constprop.111+0x66/0x70
[10251.059635] [<ffffffff815779ab>] usb_alloc_streams+0xab/0xf0
[10251.059662] [<ffffffffc0616b48>] uas_configure_endpoints+0x128/0x150 [uas]
[10251.059694] [<ffffffffc0616bac>] uas_post_reset+0x3c/0xb0 [uas]
[10251.059722] [<ffffffff815727d9>] usb_reset_device+0x1b9/0x2a0
[10251.059749] [<ffffffffc0616f42>] uas_eh_bus_reset_handler+0xb2/0x190 [uas]
[10251.059781] [<ffffffff81514293>] scsi_try_bus_reset+0x53/0x110
[10251.059808] [<ffffffff815163b7>] scsi_eh_bus_reset+0xf7/0x270
<snip>
The problem is the following call sequence (simplified):
1) usb_reset_device
2) usb_reset_and_verify_device
2) hub_port_init
3) hub_port_finish_reset
3) xhci_discover_or_reset_device
This frees xhci->devs[slot_id]->eps[ep_index].ring for all eps but 0
4) usb_get_device_descriptor
This fails
5) hub_port_init fails
6) usb_reset_and_verify_device fails, does not restore device config
7) uas_post_reset
8) xhci_alloc_streams
NULL deref on the free-ed ring
This commit fixes this by not allowing usb_alloc_streams to continue if
the device is not configured.
Note that we do allow usb_free_streams to continue after a (logical)
disconnect, as it is necessary to explicitly free the streams at the xhci
controller level.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.