Re: [PATCH] brcmfmac: change the order of things in brcmf_detach()

[Piotr Figiel <p.figiel@camlintechnologies.com>]

Hi Arend,

On Mon, Apr 29, 2019 at 12:09:21PM +0200, Arend van Spriel wrote:
> When brcmf_detach() from the bus layer upon rmmod we can no longer
> communicate. Hence we will set the bus state to DOWN and cleanup
> the event and protocol layer. The network interfaces need to be
> deleted before brcmf_cfg80211_detach() because the latter does the
> wiphy_unregister() which issues a warning if there are still network
> devices linked to the wiphy instance.

This seems to already happen - brcmf_cfg80211_detach() is called after the
interfaces are removed.

> This change solves a null pointer dereference issue which happened
> upon issueing rmmod while there are packets queued in bus protocol
> layer.
> 
> Reported-by: Rafał Miłecki <rafal@milecki.pl>
> Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
> Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
> Reviewed-by: Franky Lin <franky.lin@broadcom.com>
> Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> ---
> Hi Piotr,
> 
> While working on an issue with msgbuf protocol (used for PCIe devices)
> your change 5cdb0ef6144f ("brcmfmac: fix NULL pointer derefence during
> USB disconnect") conflicted. I suspect my reordering stuff in
> brcmf_detach() also fixes your issue so could you retest this patch,
> which basically reverts your change and applies my reordering, and see
> whether my suspicion can be confirmed.

Does the issue reported by Rafał you are trying to solve with this patch occur
on current linux-next?

Best regards,
-- 
Piotr Figiel