Re: 4.14: WARNING: CPU: 4 PID: 2895 at block/blk-mq.c:1144 with virtio-blk (also 4.12 stable)

[Jens Axboe]

On 11/21/2017 03:14 AM, Christian Borntraeger wrote:
> Bisect points to
> 
> 1b5a7455d345b223d3a4658a9e5fce985b7998c1 is the first bad commit
> commit 1b5a7455d345b223d3a4658a9e5fce985b7998c1
> Author: Christoph Hellwig <hch@xxxxxx>
> Date:   Mon Jun 26 12:20:57 2017 +0200
> 
>     blk-mq: Create hctx for each present CPU
>     
>     commit 4b855ad37194f7bdbb200ce7a1c7051fecb56a08 upstream.
>     
>     Currently we only create hctx for online CPUs, which can lead to a lot
>     of churn due to frequent soft offline / online operations.  Instead
>     allocate one for each present CPU to avoid this and dramatically simplify
>     the code.
>     
>     Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>     Reviewed-by: Jens Axboe <axboe@xxxxxxxxx>
>     Cc: Keith Busch <keith.busch@xxxxxxxxx>
>     Cc: linux-block@xxxxxxxxxxxxxxx
>     Cc: linux-nvme@xxxxxxxxxxxxxxxxxxx
>     Link: http://lkml.kernel.org/r/20170626102058.10200-3-hch@xxxxxx
>     Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>     Cc: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
>     Cc: Mike Galbraith <efault@xxxxxx>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

I wonder if we're simply not getting the masks updated correctly. I'll
take a look.

-- 
Jens Axboe