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Commit bc1978d4 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
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[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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 853609b6

kernel/itimer.c

+10 −1
Original line number Diff line number Diff line
@@ -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);