Return-path: Received: from mail-wm0-f50.google.com ([74.125.82.50]:37252 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750883AbcFRT0m (ORCPT ); Sat, 18 Jun 2016 15:26:42 -0400 Received: by mail-wm0-f50.google.com with SMTP id a66so28346604wme.0 for ; Sat, 18 Jun 2016 12:26:41 -0700 (PDT) Subject: Re: [PATCH RFC 1/2] brcmfmac: remove interface before notifying listener To: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Kalle Valo References: <1466273932-11554-1-git-send-email-zajec5@gmail.com> Cc: Franky Lin , Hante Meuleman , Pieter-Paul Giesberts , "Franky (Zhenhui) Lin" , "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" , "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" , "open list:NETWORKING DRIVERS" , open list From: Arend van Spriel Message-ID: <5765A06C.3040005@broadcom.com> (sfid-20160618_212718_841553_D0693336) Date: Sat, 18 Jun 2016 21:26:36 +0200 MIME-Version: 1.0 In-Reply-To: <1466273932-11554-1-git-send-email-zajec5@gmail.com> Content-Type: text/plain; charset=utf-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 18-06-16 20:18, Rafał Miłecki wrote: > So far when receiving event about in-firmware-interface removal we were > notifying our listener and afterwards we were removing Linux interface. > [snip] > > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c > index 9da7a4c..5fd1886 100644 > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c > @@ -18,6 +18,7 @@ > #include "brcmu_wifi.h" > #include "brcmu_utils.h" > > +#include "cfg80211.h" > #include "core.h" > #include "debug.h" > #include "tracepoint.h" > @@ -180,10 +181,16 @@ static void brcmf_fweh_handle_if_event(struct brcmf_pub *drvr, > if (ifp && ifevent->action == BRCMF_E_IF_CHANGE) > brcmf_fws_reset_interface(ifp); > > - err = brcmf_fweh_call_event_handler(ifp, emsg->event_code, emsg, data); The reason for doing this first is because we are passing the ifp, which is netdev_priv(ifp->ndev). In brcmf_remove_interface() we only unregister the netdev, which will end up (after scheduling) in brcmf_free_netdev() thus freeing the ifp. By moving the event handler function ifp may be stale already. > + if (ifp && ifevent->action == BRCMF_E_IF_DEL) { > + bool rtnl_locked = brcmf_cfg80211_vif_event_armed(drvr->config); > + > + brcmf_remove_interface(ifp, rtnl_locked); I guess rtnl_locked here means "rtnl_is_locked() by brcmfmac". It actually does not matter who is holding the rtnl_lock. At least when it is brcmfmac it is still a different task, ie. hostapd, iw, etc. Also when brcmf_cfg80211_vif_event_armed() return false there may still be some task holding the rtnl_lock. Regards, Arend