Messages in this thread | | | Date | Thu, 20 Jan 2022 13:02:06 +0100 | Subject | Re: [PATCH v2 0/7] kvm: fix latent guest entry/exit bugs | From | Christian Borntraeger <> |
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Am 20.01.22 um 12:57 schrieb Mark Rutland: > On Wed, Jan 19, 2022 at 08:30:17PM +0100, Christian Borntraeger wrote: >> >> >> Am 19.01.22 um 20:22 schrieb Mark Rutland: >>> On Wed, Jan 19, 2022 at 07:25:20PM +0100, Christian Borntraeger wrote: >>>> Am 19.01.22 um 11:58 schrieb Mark Rutland: >>>> >>>> >>>> CCing new emails for Anup and Atish so that they are aware of this thread. >>> >>> Ah; whoops. I'd meant to fix the Ccs on the patches. >>> >>> Thanks! >>> >>> [...] >>> >>>> I just gave this a spin on s390 with debugging on and I got the following: >>>> >>>> [ 457.151295] ------------[ cut here ]------------ >>>> [ 457.151311] WARNING: CPU: 14 PID: 0 at kernel/rcu/tree.c:613 rcu_eqs_enter.constprop.0+0xf8/0x118 >>> >>> Hmm, so IIUC that's: >>> >>> WARN_ON_ONCE(rdp->dynticks_nmi_nesting != DYNTICK_IRQ_NONIDLE); >>> >>> ... and we're clearly in the idle thread here. >>> >>> I wonder, is the s390 guest entry/exit *preemptible* ? >> >> Looks like debug_defconfig is indeed using preemption: >> >> CONFIG_PREEMPT_BUILD=y >> # CONFIG_PREEMPT_NONE is not set >> # CONFIG_PREEMPT_VOLUNTARY is not set >> CONFIG_PREEMPT=y >> CONFIG_PREEMPT_COUNT=y >> CONFIG_PREEMPTION=y >> CONFIG_PREEMPT_RCU=y >> CONFIG_PREEMPT_NOTIFIERS=y >> CONFIG_DEBUG_PREEMPT=y >> CONFIG_PREEMPTIRQ_TRACEPOINTS=y >> CONFIG_TRACE_PREEMPT_TOGGLE=y >> CONFIG_PREEMPT_TRACER=y >> # CONFIG_PREEMPTIRQ_DELAY_TEST is not set > > Thanks for confirming! > > Could you try with CONFIG_PROVE_RCU=y ? That can't be selected directly, but > selecting PROVE_LOCKING=y will enable it.
PROVE_LOCKING was enabled in my runs as well as PROVE_RCU.
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