linux-kernel - Re: [PATCH] Revert "xen/acpi-processor: fix enabling interrupts on syscore

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Date:	Mon, 29 Sep 2014 19:06:07 +0100
From:	David Vrabel <david.vrabel@...rix.com>
To:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC:	<sgruszka@...hat.com>, <xen-devel@...ts.xenproject.org>,
	<linux-kernel@...r.kernel.org>, <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH] Revert "xen/acpi-processor: fix enabling interrupts on
 syscore_resume"

On 29/09/14 18:55, Konrad Rzeszutek Wilk wrote:
> 
> This patch should be a good start to discussing the fix.
> 
> From 3544815f7c44508e2c9a0c55caf4a32cc8283685 Mon Sep 17 00:00:00 2001
> From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Date: Mon, 29 Sep 2014 13:48:57 -0400
> Subject: [PATCH] xen-acpi-processor: Use spinlock and GFP_ATOMIC to deal with
>  resume
> 
> hitting the IRQs being enabled during resume.
> 
> WARNING: CPU: 0 PID: 6733 at drivers/base/syscore.c:104 syscore_resume+0x9a/0xe0()
> Interrupts enabled after xen_acpi_processor_resume+0x0/0x34 [xen_acpi_processor]
> 
> Call Trace:
>  [<ffffffff81667a8b>] dump_stack+0x45/0x56
>  [<ffffffff8106921d>] warn_slowpath_common+0x7d/0xa0
>  [<ffffffff8106928c>] warn_slowpath_fmt+0x4c/0x50
>  [<ffffffffa0261bb0>] ? xen_upload_processor_pm_data+0x300/0x300 [xen_acpi_processor]
>  [<ffffffff814055fa>] syscore_resume+0x9a/0xe0
>  [<ffffffff810aef42>] suspend_devices_and_enter+0x402/0x470
>  [<ffffffff810af128>] pm_suspend+0x178/0x260
> 
> Converting the mutex to a spinlock and all of the GPF_KERNEL
> to GFP_ATOMIC take care of that.

Do we need to load this into Xen so early?  I'd much prefer not adding a
bunch of GFP_ATOMIC allocations into the resume path.

I'd probably just schedule some work in the syscore resume to do the load.

David
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