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From: Dario Faggioli <dfaggioli@suse.com>
To: "Jürgen Groß" <jgross@suse.com>,
	"Sergey Dyasli" <sergey.dyasli@citrix.com>,
	xen-devel@lists.xenproject.org
Cc: George Dunlap <george.dunlap@citrix.com>,
	Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCH] sched: fix scheduler_disable() with core scheduling
Date: Thu, 16 Apr 2020 18:10:57 +0200	[thread overview]
Message-ID: <559fe5e03caa954f6985e074940b5eb076b0af3f.camel@suse.com> (raw)
In-Reply-To: <8db96ff6-53e3-8c01-0737-5181ccc348ab@suse.com>

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On Thu, 2020-04-09 at 14:50 +0200, Jürgen Groß wrote:
> On 09.04.20 11:41, Sergey Dyasli wrote:
> > In core-scheduling mode, Xen might crash when entering ACPI S5
> > state.
> > This happens in sched_slave() during is_idle_unit(next) check
> > because
> > next->vcpu_list is stale and points to an already freed memory.
> > 
> > This situation happens shortly after scheduler_disable() is called
> > if
> > some CPU is still inside sched_slave() softirq. Current logic
> > simply
> > returns prev->next_task from sched_wait_rendezvous_in() which
> > causes
> > the described crash because next_task->vcpu_list has become
> > invalid.
> > 
> > Fix the crash by returning NULL from sched_wait_rendezvous_in() in
> > the case when scheduler_disable() has been called.
> > 
> > Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
> 
> Reviewed-by: Juergen Gross <jgross@suse.com>
> 
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>

Thanks and Regards
-- 
Dario Faggioli, Ph.D
http://about.me/dario.faggioli
Virtualization Software Engineer
SUSE Labs, SUSE https://www.suse.com/
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      parent reply	other threads:[~2020-04-16 16:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-09  9:41 [PATCH] sched: fix scheduler_disable() with core scheduling Sergey Dyasli
2020-04-09 12:50 ` Jürgen Groß
2020-04-14 12:37   ` Sergey Dyasli
2020-04-16 16:10   ` Dario Faggioli [this message]

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