From bc1978d404befacd272d0321ef749cc3192e488b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 1 Feb 2006 03:05:08 -0800 Subject: [PATCH] [PATCH] hrtimers: fixup itimer conversion 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/itimer.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/itimer.c b/kernel/itimer.c index c2c05c4ff2..6433d06855 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); -- 2.39.5