commit dbda4c0b97b18fd59b3964548361b4f92357f730
author Alan Cox <alan@redhat.com> Mon Oct 13 10:40:53 2008 +0100
committer Linus Torvalds <torvalds@linux-foundation.org> Mon Oct 13 09:51:42 2008 -0700
tree ca7e2827541aec01762f2a9c0e3155aaf49bf0ca
parent 934e6ebf96e8c1a0f299e64129fdaebc1132a427

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>

kernel/acct.c

diff --git a/kernel/acct.c b/kernel/acct.c
index dd68b90..f6006a6 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -548,7 +548,7 @@
 #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)));