Messages in this thread Patch in this message | | | Date | Tue, 7 Jul 2015 10:12:34 -0700 | From | tip-bot for Thomas Gleixner <> | Subject | [tip:timers/urgent] tick/broadcast: Prevent hrtimer recursion |
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Commit-ID: 8eb231261fdd20768db23863d00ef277de4b0543 Gitweb: http://git.kernel.org/tip/8eb231261fdd20768db23863d00ef277de4b0543 Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Tue, 7 Jul 2015 14:11:00 +0200 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Tue, 7 Jul 2015 18:46:47 +0200
tick/broadcast: Prevent hrtimer recursion
The hrtimer based broadcast vehicle can cause a hrtimer recursion which went unnoticed until we changed the hrtimer expiry code to keep track of the currently running timer.
local_timer_interrupt() local_handler() hrtimer_interrupt() expire_hrtimers() broadcast_hrtimer() send_ipis() local_handler() hrtimer_interrupt() ....
Solution is simple: Prevent the local handler call from the broadcast code when the broadcast 'device' is hrtimer based.
[ Split out from a larger combo patch ]
Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos --- kernel/time/tick-broadcast.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index d39f32c..a762040 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -265,8 +265,22 @@ static bool tick_do_broadcast(struct cpumask *mask) * Check, if the current cpu is in the mask */ if (cpumask_test_cpu(cpu, mask)) { + struct clock_event_device *bc = tick_broadcast_device.evtdev; + cpumask_clear_cpu(cpu, mask); - local = true; + /* + * We only run the local handler, if the broadcast + * device is not hrtimer based. Otherwise we run into + * a hrtimer recursion. + * + * local timer_interrupt() + * local_handler() + * expire_hrtimers() + * bc_handler() + * local_handler() + * expire_hrtimers() + */ + local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER); } if (!cpumask_empty(mask)) {
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