hrtimer: Prevent queuing of hrtimer without a function callback

The hrtimer function callback must not be NULL. It has to be specified by
the call side but it is not validated by the hrtimer code. When a hrtimer
is queued without a function callback, the kernel crashes with a null
pointer dereference when trying to execute the callback in __run_hrtimer().

Introduce a validation before queuing the hrtimer in
hrtimer_start_range_ns().

[anna-maria: Rephrase commit message]

Signed-off-by: Phil Chang <phil.chang@mediatek.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 492c14aac642bb25d7bedcd2b29e97eea5ebe0f4..b8ee320208d411743555947746a59e03a3fc027e 100644 (file)
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1285,6 +1285,8 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
        struct hrtimer_clock_base *base;
        unsigned long flags;
 
+       if (WARN_ON_ONCE(!timer->function))
+               return;
        /*
         * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
         * match on CONFIG_PREEMPT_RT = n. With PREEMPT_RT check the hard