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From: "Jürgen Groß" <jgross@suse.com>
To: Sergey Dyasli <sergey.dyasli@citrix.com>, xen-devel@lists.xenproject.org
Cc: George Dunlap <george.dunlap@citrix.com>,
	Jan Beulich <jbeulich@suse.com>,
	Dario Faggioli <dfaggioli@suse.com>
Subject: Re: [PATCH] sched: fix scheduler_disable() with core scheduling
Date: Thu, 9 Apr 2020 14:50:44 +0200	[thread overview]
Message-ID: <8db96ff6-53e3-8c01-0737-5181ccc348ab@suse.com> (raw)
In-Reply-To: <20200409094137.13836-1-sergey.dyasli@citrix.com>

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>

Good catch!

Have you seen any further problems (e.g. with cpu on/offlining) with
this patch applied?

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen


  reply	other threads:[~2020-04-09 12:51 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 [this message]
2020-04-14 12:37   ` Sergey Dyasli
2020-04-16 16:10   ` Dario Faggioli

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