From: Wei Liu <wei.liu2@citrix.com>
To: Dario Faggioli <dario.faggioli@citrix.com>
Cc: xen-devel@lists.xenproject.org, Wei Liu <wei.liu2@citrix.com>,
George Dunlap <george.dunlap@citrix.com>
Subject: Re: [for-4.8 PATCH] xen: credit2: fix wrong assert in runq_tickle().
Date: Tue, 22 Nov 2016 10:55:17 +0000 [thread overview]
Message-ID: <20161122105517.GO23528@citrix.com> (raw)
In-Reply-To: <147981141529.15399.3103284119825700755.stgit@Solace.fritz.box>
On Tue, Nov 22, 2016 at 11:43:35AM +0100, Dario Faggioli wrote:
> Since b047f888d489 ("xen: sched: leave CPUs doing tasklet
> work alone") a cpu executing a tasklet, is not marked as
> idle.
>
> Therefore:
> - avoid asserting that we can't find the idle vcpu running
> on one of them, which is not true,
> - avoid triggering a preemption on them (and add an assert
> checking that).
>
> This fixes a bug identified by OSSTest, in flight 102372
> (on ARM, but it's not at all ARM specific), where the
> ASSERT() was triggering like this:
>
> (XEN) Xen call trace:
> (XEN) [<0022af78>] sched_credit2.c#runq_tickle+0x3e8/0x61c (PC)
> (XEN) [<0022aedc>] sched_credit2.c#runq_tickle+0x34c/0x61c (LR)
> (XEN) [<0022b644>] sched_credit2.c#csched2_context_saved+0x128/0x1a4
> (XEN) [<0023303c>] context_saved+0x7c/0xa4
> (XEN) [<0024f660>] domain.c#schedule_tail+0x2b4/0x308
> (XEN) [<0024faac>] context_switch+0x80/0x94
> (XEN) [<0022ff48>] schedule.c#schedule+0x76c/0x7ec
> (XEN) [<002338d4>] softirq.c#__do_softirq+0xcc/0xec
> (XEN) [<00233968>] do_softirq+0x18/0x28
> (XEN) [<00261084>] leave_hypervisor_tail+0x58/0x88
> (XEN) [<002649d0>] entry.o#return_to_guest+0xc/0xb8
> (XEN)
> (XEN) ****************************************
> (XEN) Panic on CPU 1:
> (XEN) Assertion '!is_idle_vcpu(cur->vcpu)' failed at sched_credit2.c:1009
> (XEN) ****************************************
>
> Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
> ---
> Cc: George Dunlap <george.dunlap@citrix.com>
> Cc: Wei Liu <wei.liu2@citrix.com>
I would like to have this fix, so in principle:
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
I haven't read the content of this patch though.
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next prev parent reply other threads:[~2016-11-22 10:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-22 10:43 [for-4.8 PATCH] xen: credit2: fix wrong assert in runq_tickle() Dario Faggioli
2016-11-22 10:55 ` Wei Liu [this message]
2016-11-22 11:21 ` Jan Beulich
2016-11-22 11:38 ` Juergen Gross
2016-11-22 11:52 ` Dario Faggioli
2016-11-22 13:00 ` Jan Beulich
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