linux/drivers/usb
Alan Stern 0d00dc2611 USB: Fix race condition when removing host controllers
This patch (as1607) fixes a race that can occur if a USB host
controller is removed while a process is reading the
/sys/kernel/debug/usb/devices file.

The usb_device_read() routine uses the bus->root_hub pointer to
determine whether or not the root hub is registered.  The is not a
valid test, because the pointer is set before the root hub gets
registered and remains set even after the root hub is unregistered and
deallocated.  As a result, usb_device_read() or usb_device_dump() can
access freed memory, causing an oops.

The patch changes the test to use the hcd->rh_registered flag, which
does get set and cleared at the appropriate times.  It also makes sure
to hold the usb_bus_list_lock mutex while setting the flag, so that
usb_device_read() will become aware of new root hubs as soon as they
are registered.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Don Zickus <dzickus@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-27 09:17:49 -07:00
..
atm usb: Use eth_random_addr 2012-07-16 22:39:07 -07:00
c67x00 usb: convert drivers/usb/* to use module_platform_driver() 2011-11-28 06:48:32 +09:00
chipidea usb: chipidea: udc: don't stall endpoint if request list is empty in isr_tr_complete_low 2012-09-12 10:58:38 -07:00
class USB: cdc-wdm: fix wdm_find_device* return value 2012-09-10 15:33:00 -07:00
core USB: Fix race condition when removing host controllers 2012-09-27 09:17:49 -07:00
dwc3 usb: dwc3: gadget: fix pending isoc handling 2012-09-06 19:52:30 +03:00
early KGDB/KDB/usb-dbgp fixes and cleanups 2012-08-03 10:53:47 -07:00
gadget usb: gadget: at91udc: Don't check for ep->ep.desc 2012-09-06 19:52:29 +03:00
host USB: ohci-at91: fix null pointer in ohci_hcd_at91_overcurrent_irq 2012-09-27 09:16:38 -07:00
image USB: mdc800.c: remove dbg() usage 2012-05-01 21:33:50 -07:00
misc USB: emi62: remove __devinit* from the struct usb_device_id table 2012-08-17 17:50:45 -07:00
mon usb: Add export.h for EXPORT_SYMBOL/THIS_MODULE where needed 2011-10-31 19:31:25 -04:00
musb usb: musb: musbhsdma: fix IRQ check 2012-09-06 19:52:28 +03:00
otg This patch series contains a major revamp of how we collect entropy 2012-07-31 19:07:42 -07:00
phy usb: phy: Fix Kconfig dependency for Phy drivers 2012-06-26 16:14:33 -07:00
renesas_usbhs usb: renesas_usbhs: fixup DMA transport data alignment 2012-09-06 19:52:30 +03:00
serial USB: option: replace ZTE K5006-Z entry with vendor class rule 2012-09-11 12:34:29 -07:00
storage [SCSI] usb-storage: update usb devices for write cache quirk in quirk list. 2012-07-20 08:59:00 +01:00
wusbcore uwb & wusb: fix kconfig error 2012-01-26 11:22:42 -08:00
Kconfig gpu/mfd/usb: Fix USB randconfig problems 2012-08-20 11:52:41 -07:00
Makefile usb: phy: Fix Kconfig dependency for Phy drivers 2012-06-26 16:14:33 -07:00
README
usb-common.c usb: Provide usb_speed_string() function 2011-09-18 01:29:04 -07:00
usb-skeleton.c USB: usb-skeleton.c: remove err() usage 2012-04-27 11:24:45 -07:00

README

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.