Re: Kernel oops

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Thu, Jul 27, 2017 at 02:44:37PM -0600, Jason Gunthorpe wrote:
> 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

Hi Jason,

I queued it [1] for submission, once the IPoIB fixes [2] will be
accepted, I'll submit it.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/commit/?h=rdma-rc&id=38a974d578451dbbde0c40fc2d81fba44027a338
[2] http://marc.info/?l=linux-rdma&m=150109276402195&w=2

>
> Jason
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