Re: [PATCH] RDMA/core: Fix bogus WARN_ON during ib_unregister_device_queued()

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Jun 26, 2020 at 02:49:10PM -0300, Jason Gunthorpe wrote:
> ib_unregister_device_queued() can only be used by drivers using the new
> dealloc_device callback flow, and it has a safety WARN_ON to ensure
> drivers are using it properly.
> 
> However, if unregister and register are raced there is a special
> destruction path that maintains the uniform error h andling semantic of
> 'caller does ib_dealloc_device() on failure'. This requires disabling the
> dealloc_device callback which triggers the WARN_ON.
> 
> Instead of using NULL to disable the callback use a special function
> pointer so the WARN_ON does not trigger.
> 
> Reported-by: syzbot+4088ed905e4ae2b0e13b@syzkaller.appspotmail.com
> Suggested-by: Hillf Danton <hdanton@sina.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
> ---
>  drivers/infiniband/core/device.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> As outlined by Hillf, seems like it is OK.

Applied to for-next

Jason