From: "Chen, Yu C" <yu.c.chen@intel.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <lenb@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@suse.de>,
Brian Gerst <brgerst@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Varun Koyyalagunta <cpudebug@centtech.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 1/4][RFC v2] PM / sleep: Avoid accessing frozen_cpus if it is NULL
Date: Sun, 26 Jun 2016 01:16:54 +0000 [thread overview]
Message-ID: <36DF59CE26D8EE47B0655C516E9CE6402877B7D6@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <20160625165113.GA4362@amd>
Hi,
> -----Original Message-----
> From: Pavel Machek [mailto:pavel@ucw.cz]
> Sent: Sunday, June 26, 2016 12:51 AM
> To: Chen, Yu C
> Cc: linux-pm@vger.kernel.org; x86@kernel.org; Rafael J. Wysocki; Len Brown;
> Peter Zijlstra; H. Peter Anvin; Borislav Petkov; Brian Gerst; Thomas Gleixner;
> Ingo Molnar; Varun Koyyalagunta; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH 1/4][RFC v2] PM / sleep: Avoid accessing frozen_cpus if it
> is NULL
>
> On Sun 2016-06-26 00:18:30, Chen Yu wrote:
> > frozen_cpus might be NULL if the allocation in previous
> > alloc_frozen_cpus failed, when CONFIG_CPUMASK_OFFSTACK is set.
> >
> > This patch avoid accessing this cpumask if it is NULL.
> >
> > Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> > ---
> > kernel/cpu.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/kernel/cpu.c b/kernel/cpu.c index d948e44..d25266e 100644
> > --- a/kernel/cpu.c
> > +++ b/kernel/cpu.c
> > @@ -1021,6 +1021,8 @@ int disable_nonboot_cpus(void) {
> > int cpu, first_cpu, error = 0;
> >
> > + if (frozen_cpus == NULL)
> > + return -ENOMEM;
> > cpu_maps_update_begin();
> > first_cpu = cpumask_first(cpu_online_mask);
> > /*
>
> I'd say that whoever allocates frozen_cpus should just abort the hibernation if
> there's not enough memory for the operation...? This seems like checking for
> the problem too late.
>
The allocation of frozen_cpus is alloc_frozen_cpus, which is in core_initcall,
and do_initcall during boot up seems not to care about the return value from
these functions. So I think either we add the check in disable_nonboot_cpus, or
we can set noresume = 1 and nohibernate = 1 if alloc_frozen_cpus fails.
thanks,
Yu
next prev parent reply other threads:[~2016-06-26 1:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-25 16:18 [PATCH 0/4][RFC v2] x86, hotplug: Use hlt instead of mwait when resuming from hibernation Chen Yu
2016-06-25 16:18 ` [PATCH 1/4][RFC v2] PM / sleep: Avoid accessing frozen_cpus if it is NULL Chen Yu
2016-06-25 16:51 ` Pavel Machek
2016-06-26 1:16 ` Chen, Yu C [this message]
2016-06-26 4:25 ` Chen, Yu C
2016-06-25 16:18 ` [PATCH 2/4][RFC v2] PM / sleep: Introduce arch-specific hook for disable/enable nonboot cpus Chen Yu
2016-06-25 16:51 ` Pavel Machek
2016-06-26 1:19 ` Chen, Yu C
2016-10-07 19:31 ` Andy Lutomirski
2016-10-08 16:58 ` Chen Yu
2016-10-11 15:42 ` Pavel Machek
2016-06-25 16:18 ` [PATCH 3/4][RFC v2] PM / hibernate: introduce a flag to indicate resuming from hibernation Chen Yu
2016-06-25 16:53 ` Pavel Machek
2016-06-26 1:34 ` Chen, Yu C
2016-06-25 16:19 ` [PATCH 4/4] x86, hotplug: Use hlt instead of mwait when " Chen Yu
2016-10-07 19:47 ` Andy Lutomirski
2016-10-08 10:31 ` Rafael J. Wysocki
2016-10-16 16:50 ` Andy Lutomirski
2016-10-18 0:30 ` Rafael J. Wysocki
2016-10-18 1:21 ` Andy Lutomirski
2016-10-08 16:54 ` Chen Yu
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