Subject: Re: [Bugfix 4/5] x86/irq: Fix a race condition between vector
 assigning and cleanup
To: Jiang Liu <jiang.liu@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>
References: <alpine.DEB.2.11.1511270923250.3572@nanos>
 <1448870970-1461-1-git-send-email-jiang.liu@linux.intel.com>
 <1448870970-1461-4-git-send-email-jiang.liu@linux.intel.com>
CC: <linux-kernel@vger.kernel.org>, <x86@kernel.org>
From: Joe Lawrence <joe.lawrence@stratus.com>
Message-ID: <565E234B.6030808@stratus.com>
Date: Tue, 1 Dec 2015 17:46:35 -0500
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On 11/30/2015 03:09 AM, Jiang Liu wrote:
> Joe Lawrence <joe.lawrence@stratus.com> reported an use after release
> issue related to x86 IRQ management code. Please refer to following
> link for more information:
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1026840.html
> 
> Thomas pointed out that it's caused by a race condition between
> __assign_irq_vector() and __send_cleanup_vector(). Based on Thomas'
> draft patch, we solve this race condition by:
> 1) Use move_in_progress to signal that an IRQ cleanup IPI is needed
> 2) Use old_domain to save old CPU mask for IRQ cleanup
> 3) Use vector to protect move_in_progress and old_domain
> 
> This bugfix patch also helps to get rid of that atomic allocation in
> __send_cleanup_vector().
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---

[ ... snip ... ]

Jiang, Thomas,

Last night I ran with Jiang's five-patch-set on top of 4.3.  Tests
started with regular sysfs device removal of mpt HBAs, then later I
added disk stress (the disks are software RAID1 across the HBAs) .. no
issues.

I'll kick off some tougher surprise device removal tests tonight to
further kick the tires.

-- Joe
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