Subject: Re: [PATCH net v2] xdp: xdp_mem_allocator can be NULL in trace_mem_connect().

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Wed, 09 Mar 2022 22:52:14 +0100

Sebastian Andrzej Siewior <[email-masked]> writes:

> Since the commit mentioned below __xdp_reg_mem_model() can return a NULL
> pointer. This pointer is dereferenced in trace_mem_connect() which leads
> to segfault.
>
> The trace points (mem_connect + mem_disconnect) were put in place to
> pair connect/disconnect using the IDs. The ID is only assigned if
> __xdp_reg_mem_model() does not return NULL. That connect trace point is
> of no use if there is no ID.
>
> Skip that connect trace point if xdp_alloc is NULL.
>
> [ Toke Høiland-Jørgensen delivered the reasoning for skipping the trace
>   point ]
>
> Fixes: 4a48ef70b93b8 ("xdp: Allow registering memory model without rxq reference")
> Signed-off-by: Sebastian Andrzej Siewior <[email-masked]>

With Steven's fix:

Acked-by: Toke Høiland-Jørgensen <[email-masked]>