On Mon, Feb 10, 2014 at 07:59:39PM +0100, poma wrote:

On 10.02.2014 11:06, Thomas Gleixner wrote:

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On Mon, 10 Feb 2014, poma wrote:

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[ 83.558551] [<ffffffff81025b17>] amd_e400_idle+0x87/0x130

So this seems to happen only on AMD machines which use that e400 idle mode. I have no idea at the moment whats wrong there. I'll find one of those machines and try to reproduce.

I tried to debug that warn as well. Even if I found machine with proper family and model number, HW C1E bug do not happen there, hence I just hack kernel to always use amd_e400_idle (and remove AMD rdmsr specific instructions to do not crash). That make issue 100% reproducible when suspend/resume.

It happens when cpu become idle, call CLOCK_EVT_NOTIFY_BROADCAST_ENTER, but before CLOCK_EVT_NOTIFY_BROADCAST_EXIT, interrupt trigger on that cpu. IRQ is handled by hrtimer code, which want to switch to hres and call:

tick_switch_to_oneshot() -> ... -> tick_broadcast_setup_oneshot()

Since we have already proper handler there, last procedure clear tick_broadcast_oneshot_mask, but tick_broadcast_pending_mask stay set. When amd_e400_idle next time call CLOCK_EVT_NOTIFY_BROADCAST_ENTER, the warning will happen.

I came with a below patch, which also clear pending mask, but perhaps oneshot_mask should not be cleared on tick_broadcast_setup_oneshot(), or should be cleared only conditionally, or some other solution is needed. Anyway, patch make the warning gone on my hacked setup, I was waiting for testing results on real C1E hardware.

Thanks Stanislaw

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 43780ab..98977a5 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -756,6 +756,7 @@ out: static void tick_broadcast_clear_oneshot(int cpu) { cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask); + cpumask_clear_cpu(cpu, tick_broadcast_pending_mask); }

static void tick_broadcast_init_next_event(struct cpumask *mask,