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/openbmc/linux/drivers/usb/core/
H A Ddevices.c0a231403 Wed Sep 26 12:09:53 CDT 2012 Alan Stern <stern@rowland.harvard.edu> 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>
0a231403 Wed Sep 26 12:09:53 CDT 2012 Alan Stern <stern@rowland.harvard.edu> 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>
H A Dhcd.c0a231403 Wed Sep 26 12:09:53 CDT 2012 Alan Stern <stern@rowland.harvard.edu> 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>
0a231403 Wed Sep 26 12:09:53 CDT 2012 Alan Stern <stern@rowland.harvard.edu> 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>