CVS commit: src/sys/dev/usb

["Michael van Elst" <mlelstv%netbsd.org@localhost>]

Module Name:    src
Committed By:   mlelstv
Date:           Sat May 14 10:52:29 UTC 2016

Modified Files:
        src/sys/dev/usb: ucom.c

Log Message:
All com devices have an issue that they sleep in the final close
when they signal a hangup while still using the device. This allows
a concurrent open to succeed without proper locking because it
only checks the state of the tty layer.

This issue triggers an assertion in ucom due to a reused USB xfer,
but it can also cause misbehaviour in other com devices.

For now in ucom:
- make open block while close is in progress
- also serialize close operations


To generate a diff of this commit:
cvs rdiff -u -r1.112 -r1.113 src/sys/dev/usb/ucom.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.