]> git.karo-electronics.de Git - linux-beck.git/commit
USB: fix substandard locking for the sysfs files
authorAlan Stern <stern@rowland.harvard.edu>
Tue, 24 Sep 2013 19:43:39 +0000 (15:43 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 26 Sep 2013 00:27:01 +0000 (17:27 -0700)
commit232275a089dfd2e77377a85f11d0a4e3ca60e612
tree14d96e68ff15d0751996e123ff6c9e7e8ff232b5
parent9a37a50349c8d6a7adcee21cefae407fb2f8c623
USB: fix substandard locking for the sysfs files

This patch straightens out some locking issues in the USB sysfs
interface:

Deauthorization will destroy existing configurations.
Attributes that read from udev->actconfig need to lock the
device to prevent races.  Likewise for the rawdescriptor
values.

Attributes that access an interface's current alternate
setting should use ACCESS_ONCE() to obtain the cur_altsetting
pointer, to protect against concurrent altsetting changes.

The supports_autosuspend() attribute routine accesses values
from an interface's driver, so it should lock the interface
(rather than the usb_device) to protect against concurrent
unbinds.  Once this is done, the routine can be simplified
considerably.

Scalar values that are stored directly in the usb_device structure are
always available.  They do not require any locking.  The same is true
of the cached interface string descriptor, because it is not
deallocated until the usb_host_interface structure is destroyed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/core/sysfs.c