[PATCH] hrtimers: fixup itimer conversion

bc1978d4 · Thomas Gleixner <[email protected]> · 2006-02-01 03:05:08 -08:00

The itimer conversion removed the locking which protects the timer and
variables in the shared signal structure.  Steven Rostedt found the problem in
the latest -rt patches.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: bc1978d404befacd272d0321ef749cc3192e488b
Parents: 853609b6

Changes

1 files changed · +10 −1

File	Status	Add	Del	Content
kernel/itimer.c	modified	+10	−1	View file

kernel/itimer.c

View file

diff --git a/kernel/itimer.c b/kernel/itimer.c
index c2c05c4..6433d06 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -49,9 +49,11 @@ int do_getitimer(int which, struct itimerval *value)
 
 	switch (which) {
 	case ITIMER_REAL:
+		spin_lock_irq(&tsk->sighand->siglock);
 		value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
 		value->it_interval =
 			ktime_to_timeval(tsk->signal->it_real_incr);
+		spin_unlock_irq(&tsk->sighand->siglock);
 		break;
 	case ITIMER_VIRTUAL:
 		read_lock(&tasklist_lock);
@@ -150,8 +152,14 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 
 	switch (which) {
 	case ITIMER_REAL:
+again:
+		spin_lock_irq(&tsk->sighand->siglock);
 		timer = &tsk->signal->real_timer;
-		hrtimer_cancel(timer);
+		/* We are sharing ->siglock with it_real_fn() */
+		if (hrtimer_try_to_cancel(timer) < 0) {
+			spin_unlock_irq(&tsk->sighand->siglock);
+			goto again;
+		}
 		if (ovalue) {
 			ovalue->it_value = itimer_get_remtime(timer);
 			ovalue->it_interval
@@ -162,6 +170,7 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 		expires = timeval_to_ktime(value->it_value);
 		if (expires.tv64 != 0)
 			hrtimer_start(timer, expires, HRTIMER_REL);
+		spin_unlock_irq(&tsk->sighand->siglock);
 		break;
 	case ITIMER_VIRTUAL:
 		nval = timeval_to_cputime(&value->it_value);