fix console change race exposed by CFS
authorJan Lübbe <jluebbe@lasnet.de>
Sat, 29 Sep 2007 16:47:51 +0000 (18:47 +0200)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Sat, 29 Sep 2007 17:00:15 +0000 (10:00 -0700)
commita64314e62d89562b6fc77593648bec3acc35bf61
tree964aba05c1293c2436088905001595a8209e44d1
parented7fdff5d6754f9ef9e47bbf0b171d3d96fb7e41
fix console change race exposed by CFS

The new behaviour of CFS exposes a race which occurs if a switch is
requested when vt_mode.mode is VT_PROCESS.

The process with vc->vt_pid is signaled before vc->vt_newvt is set.
This causes the switch to fail when triggered by the monitoing process
because the target is still -1.

[ If the signal sending fails, the subsequent "reset_vc(vc)" will then
  reset vt_newvt to -1, so this works for that case too.   - Linus ]

Signed-off-by: Jan Lübbe <jluebbe@lasnet.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/char/vt_ioctl.c