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authorAlan Stern <stern@rowland.harvard.edu>2009-04-14 11:31:02 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2009-04-23 14:15:26 -0700
commit2d93148ab6988cad872e65d694c95e8944e1b626 (patch)
tree1b2e406958336061cce7b262ccdc5752094a23fc /drivers/usb/storage
parent091069740304c979f957ceacec39c461d0192158 (diff)
USB: serial: fix lifetime and locking problems
This patch (as1229) fixes a few lifetime and locking problems in the usb-serial driver. The main symptom is that an invalid kevent is created when the serial device is unplugged while a connection is active. Ports should be unregistered when device is disconnected, not when the parent usb_serial structure is deallocated. Each open file should hold a reference to the corresponding port structure, and the reference should be released when the file is closed. serial->disc_mutex should be acquired in serial_open(), to resolve the classic race between open and disconnect. serial_close() doesn't need to hold both serial->disc_mutex and port->mutex at the same time. Release the subdriver's module reference only after releasing all the other references, in case one of the release routines needs to invoke some code in the subdriver module. Replace a call to flush_scheduled_work() (which is prone to deadlocks) with cancel_work_sync(). Also, add a call to cancel_work_sync() in the disconnect routine. Reduce the scope of serial->disc_mutex in serial_disconnect(). The only place it really needs to protect is where the "disconnected" flag is set. This fixes the bug reported in http://bugs.freedesktop.org/show_bug.cgi?id=20703 Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Dan Williams <dcbw@redhat.com> Tested-by: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Oliver Neukum <oliver@neukum.org> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/storage')
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