Commits
Havard Skinnemoen committed bbf54d17703
USB: cdc-acm: Fix disconnect() vs close() race commit 5dc2470c602da8851907ec18942cd876c3b4ecc1 upstream. There's a race between the USB disconnect handler and the TTY close handler which may cause the acm object to be freed while it's still being used. This may lead to things like http://article.gmane.org/gmane.linux.usb.general/54250 and https://lkml.org/lkml/2011/5/29/64 This is the simplest fix I could come up with. Holding on to open_mutex while closing the TTY device prevents acm_disconnect() from freeing the acm object between acm->port.count drops to 0 and the TTY side of the cleanups are finalized. Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com> Cc: Oliver Neukum <oliver@neukum.name> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>