The USB MSC device structure contains a "ready" state that can be either
"ready", "not ready" or "detached". The last one can only be assigned
when the device is completely unresponsive and gets forcefully logically
detached via usb_detach_device(). This call (at least in the current
version) also calls all destructors and frees the complete usbdev_t
structure (including the MSC specific part), which unfortunately makes
storing the "detached" state in that very structure a little pointless.
This patch reduces the "ready" value to a simple boolean and makes sure
that all detachment cases immediately return from the MSC driver,
carefully avoiding any use-after-free opportunities.
BUG=None
TEST=Unplug a USB stick from a Pit/Kirby in depthcharge and make sure
the machine doesn't crash.
Change-Id: Iff1c0849f9ce7c95d399bb9a1a0a94469951194d
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170667
fd4529f37f