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authorPreeti U Murthy <preeti@linux.vnet.ibm.com>2015-03-18 16:19:27 +0530
committerIngo Molnar <mingo@kernel.org>2015-03-23 10:50:05 +0100
commita127d2bcf1fbc8c8e0b5cf0dab54f7d3ff50ce47 (patch)
treeba7b28d14f48b4f190b96401fe96cdec682e828b /drivers/clocksource/fsl_ftm_timer.c
parentbc465aa9d045feb0e13b4a8f32cc33c1943f62d6 (diff)
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timers/tick/broadcast-hrtimer: Fix suspicious RCU usage in idle loop
The hrtimer mode of broadcast queues hrtimers in the idle entry path so as to wakeup cpus in deep idle states. The associated call graph is : cpuidle_idle_call() |____ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, ....)) |_____tick_broadcast_set_event() |____clockevents_program_event() |____bc_set_next() The hrtimer_{start/cancel} functions call into tracing which uses RCU. But it is not legal to call into RCU in cpuidle because it is one of the quiescent states. Hence protect this region with RCU_NONIDLE which informs RCU that the cpu is momentarily non-idle. As an aside it is helpful to point out that the clock event device that is programmed here is not a per-cpu clock device; it is a pseudo clock device, used by the broadcast framework alone. The per-cpu clock device programming never goes through bc_set_next(). Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: linuxppc-dev@ozlabs.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Link: http://lkml.kernel.org/r/20150318104705.17763.56668.stgit@preeti.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/clocksource/fsl_ftm_timer.c')
0 files changed, 0 insertions, 0 deletions