From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH] doc: add known igb_uio device hot-unplug
	issue
Date: Tue, 20 Nov 2018 10:02:12 -0800
Message-ID: <20181120100212.150a6c73@xeon-e3>
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Cc: marko.kovacevic@intel.com, john.mcnamara@intel.com,
 qi.z.zhang@intel.com, ferruh.yigit@intel.com, thomas@monjalon.net,
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To: Jeff Guo <jia.guo@intel.com>
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On Tue, 20 Nov 2018 23:09:31 +0800
Jeff Guo <jia.guo@intel.com> wrote:

> When device has been bound to igb_uio driver and application is running,
> hot-unplugging the device may cause kernel crash.
> 
> Signed-off-by: Jeff Guo <jia.guo@intel.com>
> ---
>  doc/guides/rel_notes/known_issues.rst | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
> index 95e4ce6..dfe0565 100644
> --- a/doc/guides/rel_notes/known_issues.rst
> +++ b/doc/guides/rel_notes/known_issues.rst
> @@ -759,3 +759,24 @@ Netvsc driver and application restart
>  
>  **Driver/Module**:
>     ``uio_hv_generic`` module.
> +
> +
> +kernel crash when hot-unplug igb_uio device while DPDK application is running
> +-----------------------------------------------------------------------------
> +
> +**Description**:
> +   When device has been bound to igb_uio driver and application is running, hot-unplugging
> +   the device may cause kernel crash.
> +
> +**Reason**:
> +   When device is hot-unplugged, igb_uio driver will be removed which will destroy uio resources.
> +   Later trying to access any uio resource will cause kernel crash.
> +
> +**Resolution/Workaround**:
> +   If using DPDK for PCI HW hot-unplug, prefer to bind device with VFIO instead of IGB_UIO.
> +
> +**Affected Environment/Platform**:
> +    ALL.
> +
> +**Driver/Module**:
> +   ``igb_uio`` module.

Surely this is fixable. What is the back trace in the kernel? How can it be reproduced with some
common hardware (or hypervisor).  Will it happen with KVM?