clockevents: Don't allow dummy broadcast timers
Currently tick_check_broadcast_device doesn't reject clock_event_devices with CLOCK_EVT_FEAT_DUMMY, and may select them in preference to real hardware if they have a higher rating value. In this situation, the dummy timer is responsible for broadcasting to itself, and the core clockevents code may attempt to call non-existent callbacks for programming the dummy, eventually leading to a panic. This patch makes tick_check_broadcast_device always reject dummy timers, preventing this problem. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Jon Medhurst (Tixy) <tixy@linaro.org> Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -67,7 +67,8 @@ static void tick_broadcast_start_periodic(struct clock_event_device *bc)
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*/
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*/
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int tick_check_broadcast_device(struct clock_event_device *dev)
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int tick_check_broadcast_device(struct clock_event_device *dev)
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{
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{
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if ((tick_broadcast_device.evtdev &&
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if ((dev->features & CLOCK_EVT_FEAT_DUMMY) ||
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(tick_broadcast_device.evtdev &&
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tick_broadcast_device.evtdev->rating >= dev->rating) ||
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tick_broadcast_device.evtdev->rating >= dev->rating) ||
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(dev->features & CLOCK_EVT_FEAT_C3STOP))
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(dev->features & CLOCK_EVT_FEAT_C3STOP))
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return 0;
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return 0;
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