tree c48dc5283ca4f01005295a97a28e532818aedce6
parent 5393f780277165f282a37ed82dd878159ec9dad5
author Alan Cox <alan@redhat.com> 1232026225 +0000
committer Linus Torvalds <torvalds@linux-foundation.org> 1232052515 -0800

tty: Fix race in the flush for some ldiscs

If you issue an ioctl to flush a tty as the line discipline is changing or
otherwise unplugged you can get a crash. The bug is very old but the rest
of the BKL lock dropping and some very "good" luck on Ingo's part caught
an example.

Use the correct ldisc_ref form so that we wait for the ldisc change to
complete and then flush

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>