Re: Kernel oops

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Thu, Jul 27, 2017 at 03:54:07PM +0300, Matan Barak wrote:

> Digging a bit, we found a fix that might be related to this issue.
> I would be happy if you could try that and report if it solved this problem.
> We plan to send it soon.

Yep this looks like it.

FWIW, it causes random kernel memory corruption and failures in my
experience, I was very lucky to get such a clean oops the first time..

> commit 1d4ecbf034193f000fe6686586c40ab4b2a95da1
> Author: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Date:   Thu Jul 27 15:49:00 2017 +0200
> 
>     IB/uverbs: Fix device cleanup
> 
>     Uverbs device should be cleaned up only when there is no
>     potential usage of.
> 
>     As part of ib_uverbs_remove_one which might be triggered upon reset flow
>     the device reference count is decreased as expected and leave the final
>     cleanup to the FDs that were opened.
> 
>     Current code increases reference count upon opening a new command FD and
>     decreases it upon closing the file. The event FD is opened internally
>     and rely on the command FD by taking on it a reference count.
> 
>     In case that the command FD was closed and just later the event FD we
>     may ensure that the device resources as of srcu are still alive as they
>     are still in use.
> 
>     Fixing the above by moving the reference count decreasing to the place
>     where the command FD is really freed instead of doing that when it was
>     just closed.
> 
>     Signed-off-by: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>     Reviewed-by: Matan Barak <matanb-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

Reviewed-by: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
Tested-by: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>

Please add a fixes line

Jason
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