From: Wei Liu <wei.liu@kernel.org>
To: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
Cc: Gaurav Kohli <gauravkohli@linux.microsoft.com>,
KY Srinivasan <kys@microsoft.com>,
Dexuan Cui <decui@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"wei.liu@kernel.org" <wei.liu@kernel.org>,
"bp@alien8.de" <bp@alien8.de>
Subject: Re: [PATCH v2] x86/hyperv: Remove unregister syscore call from Hyper-V cleanup
Date: Tue, 29 Nov 2022 17:57:08 +0000 [thread overview]
Message-ID: <Y4ZH9KU7CFgZduoH@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <BYAPR21MB168846312294BFCD2437B4D6D7139@BYAPR21MB1688.namprd21.prod.outlook.com>
On Mon, Nov 28, 2022 at 07:23:32PM +0000, Michael Kelley (LINUX) wrote:
> From: Gaurav Kohli <gauravkohli@linux.microsoft.com> Sent: Friday, November 25, 2022 10:15 PM
> >
> > Hyper-V cleanup code comes under panic path where preemption and irq
> > is already disabled. So calling of unregister_syscore_ops might schedule
> > out the thread even for the case where mutex lock is free.
> > hyperv_cleanup
> > unregister_syscore_ops
> > mutex_lock(&syscore_ops_lock)
> > might_sleep
> > Here might_sleep might schedule out this thread, where voluntary preemption
> > config is on and this thread will never comes back. And also this was added
> > earlier to maintain the symmetry which is not required as this can comes
> > during crash shutdown path only.
> >
> > To prevent the same, removing unregister_syscore_ops function call.
> >
> > Signed-off-by: Gaurav Kohli <gauravkohli@linux.microsoft.com>
> > ---
[...]
>
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>
>
Applied to hyperv-next. Thanks.
prev parent reply other threads:[~2022-11-29 17:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-26 6:14 [PATCH v2] x86/hyperv: Remove unregister syscore call from Hyper-V cleanup Gaurav Kohli
2022-11-28 19:23 ` Michael Kelley (LINUX)
2022-11-29 17:57 ` Wei Liu [this message]
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