Re: [PATCH rdma-rc 2/2] RDMA/core: Initialize lock when allocate a rdma_hw_stats structure

[Jason Gunthorpe]

On Tue, Oct 26, 2021 at 11:27:57AM +0300, Leon Romanovsky wrote:
> On Mon, Oct 25, 2021 at 11:50:43AM -0300, Jason Gunthorpe wrote:
> > On Sun, Oct 24, 2021 at 09:08:21AM +0300, Leon Romanovsky wrote:
> > > From: Mark Zhang <markzhang@xxxxxxxxxx>
> > > 
> > > Initialize the rdma_hw_stats "lock" field when do allocation, to fix the
> > > warning below. Then we don't need to initialize it in sysfs, remove it.
> > 
> > This is a fine cleanup, but this does not describe the bug properly,
> > or have the right fixes line..
> 
> I think that this Fixes line should be instead.
> Fixes: 0a0800ce2a6a ("RDMA/core: Add a helper API rdma_free_hw_stats_struct")

No, I don't think so, it should be the commit that added
alloc_and_bind()

> > The issue is here:
> > 
> > static struct rdma_counter *alloc_and_bind(struct ib_device *dev, u32 port,
> > 					   struct ib_qp *qp,
> > 					   enum rdma_nl_counter_mode mode)
> > {
> > 	counter->stats = dev->ops.counter_alloc_stats(counter);
> > 	if (!counter->stats)
> > 		goto err_stats;
> > 
> > Which does not init counter->stat's mutex.
> 
> This is exactly what Mark is doing here.
> 
> alloc_and_bind()
>  -> dev->ops.counter_alloc_stats
>   -> mlx5_ib_counter_alloc_stats
>    -> do_alloc_stats()
>     -> rdma_alloc_hw_stats_struct()
>      -> mutex_init(&stats->lock); <- Mark's change.

Yes, I know, the patch is fine, the commit message just needs to be
accurate
 
> > And trim the oops reports, don't include the usless ? fns, timestamps
> > or other junk.
> 
> I don't like when people "beatify" kernel reports, many times whey are
> removing too much information.

There is too much junk in the raw oops messages

Jason