linux-kernel - Re: [PATCH] xen/cpuhotplug: Fix initial CPU offlining for PV(H) guests

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <8a94d819-5143-58e2-9bd2-1cc341ba3a80@suse.com>
Date:   Mon, 11 May 2020 10:16:07 +0200
From:   Jürgen Groß <jgross@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Cc:     sstabellini@...nel.org
Subject: Re: [PATCH] xen/cpuhotplug: Fix initial CPU offlining for PV(H)
 guests

On 09.05.20 00:28, Boris Ostrovsky wrote:
> Commit a926f81d2f6c ("xen/cpuhotplug: Replace cpu_up/down() with
> device_online/offline()") replaced cpu_down() with device_offline()
> call which requires that the CPU has been registered before. This
> registration, however, happens later from topology_init() which
> is called as subsys_initcall(). setup_vcpu_hotplug_event(), on the
> other hand, is invoked earlier, during arch_initcall().
> 
> As result, booting a PV(H) guest with vcpus < maxvcpus causes a crash.
> 
> Move setup_vcpu_hotplug_event() (and therefore setup_cpu_watcher()) to
> late_initcall(). In addition, instead of performing all offlining steps
> in setup_cpu_watcher() simply call disable_hotplug_cpu().
> 
> Fixes: a926f81d2f6c (xen/cpuhotplug: Replace cpu_up/down() with device_online/offline()"
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>

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


Juergen