From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] net: systemport: Fix wake-up interrupt race during resume Date: Tue, 02 Oct 2018 17:35:26 -0700 (PDT) Message-ID: <20181002.173526.155463905341442781.davem@davemloft.net> References: <20181002235204.26135-1-f.fainelli@gmail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: f.fainelli@gmail.com Return-path: In-Reply-To: <20181002235204.26135-1-f.fainelli@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Florian Fainelli Date: Tue, 2 Oct 2018 16:52:03 -0700 > The AON_PM_L2 is normally used to trigger and identify the source of a > wake-up event. Since the RX_SYS clock is no longer turned off, we also > have an interrupt being sent to the SYSTEMPORT INTRL_2_0 controller, and > that interrupt remains active up until the magic packet detector is > disabled which happens much later during the driver resumption. > > The race happens if we have a CPU that is entering the SYSTEMPORT > INTRL2_0 handler during resume, and another CPU has managed to clear the > wake-up interrupt during bcm_sysport_resume_from_wol(). In that case, we > have the first CPU stuck in the interrupt handler with an interrupt > cause that has been cleared under its feet, and so we keep returning > IRQ_NONE and we never make any progress. > > This was not a problem before because we would always turn off the > RX_SYS clock during WoL, so the SYSTEMPORT INTRL2_0 would also be turned > off as well, thus not latching the interrupt. > > The fix is to make sure we do not enable either the MPD or > BRCM_TAG_MATCH interrupts since those are redundant with what the > AON_PM_L2 interrupt controller already processes and they would cause > such a race to occur. > > Fixes: bb9051a2b230 ("net: systemport: Add support for WAKE_FILTER") > Fixes: 83e82f4c706b ("net: systemport: add Wake-on-LAN support") > Signed-off-by: Florian Fainelli Applied, thanks Florian.