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authorSamuel Ortiz <sameo@openedhand.com>2007-10-01 01:20:12 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-01 07:52:23 -0700
commit8792f961ba8057d9f27987def3600253a3ba060f (patch)
treed12f795ab089e215e6e42c962c1abf06f70c3010 /drivers/char
parent4047727e5ae33f9b8d2b7766d1994ea6e5ec2991 (diff)
VT ioctl race fix
When calling the RELDISP VT ioctl, we are reading vt_newvt while the console workqueue could be messing with it (through change_console()). We fix this race by taking the console semaphore before reading vt_newvt. Signed-off-by: Samuel Ortiz <sameo@openedhand.com> Acked-by: Antonino Daplas <adaplas@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/vt_ioctl.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c
index 045e6888d15..c799b7f7bbb 100644
--- a/drivers/char/vt_ioctl.c
+++ b/drivers/char/vt_ioctl.c
@@ -770,6 +770,7 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
/*
* Switching-from response
*/
+ acquire_console_sem();
if (vc->vt_newvt >= 0) {
if (arg == 0)
/*
@@ -784,7 +785,6 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
* complete the switch.
*/
int newvt;
- acquire_console_sem();
newvt = vc->vt_newvt;
vc->vt_newvt = -1;
i = vc_allocate(newvt);
@@ -798,7 +798,6 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
* other console switches..
*/
complete_change_console(vc_cons[newvt].d);
- release_console_sem();
}
}
@@ -810,9 +809,12 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
/*
* If it's just an ACK, ignore it
*/
- if (arg != VT_ACKACQ)
+ if (arg != VT_ACKACQ) {
+ release_console_sem();
return -EINVAL;
+ }
}
+ release_console_sem();
return 0;