tree a8df0ce3aafc97968a354e736305a3fc807f1dea
parent 1d64b9cb1dc2a7cd521444e3d908adeccd026356
author Michal Januszewski <spock@gentoo.org> 1175496591 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1175533569 -0700

[PATCH] vt: fix potential race in VT_WAITACTIVE handler

On a multiprocessor machine the VT_WAITACTIVE ioctl call may return 0 if
fg_console has already been updated in redraw_screen() but the console
switch itself hasn't been completed.  Fix this by checking fg_console in
vt_waitactive() with the console sem held.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
Acked-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>