tty: Fix abusers of current->sighand->tty

Various people outside the tty layer still stick their noses in behind the
scenes. We need to make sure they also obey the locking and referencing rules.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index dd68b9059418..f6006a60df5d 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -548,7 +548,7 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 #endif
 
         spin_lock_irq(&current->sighand->siglock);
-        tty = current->signal->tty;
+        tty = current->signal->tty;     /* Safe as we hold the siglock */
         ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
         ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
         ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));