Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:56630 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751485AbcK2SQv (ORCPT ); Tue, 29 Nov 2016 13:16:51 -0500 Subject: Re: ath10k: Fix soft lockup during firmware crash/hw-restart To: Mohammed Shafi Shajakhan , ath10k@lists.infradead.org References: <1480430762-15995-1-git-send-email-mohammed@qca.qualcomm.com> Cc: mohammed@codeaurora.org, linux-wireless@vger.kernel.org From: Ben Greear Message-ID: <1a44a3e9-3d67-30a5-0325-a65003ebe1fc@candelatech.com> (sfid-20161129_191654_827660_FCF4E998) Date: Tue, 29 Nov 2016 10:16:50 -0800 MIME-Version: 1.0 In-Reply-To: <1480430762-15995-1-git-send-email-mohammed@qca.qualcomm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Is this something for stable? And if so, how far back should it be applied? I'll add this patch to my 4.9 tree and test it... Thanks, Ben On 11/29/2016 06:46 AM, Mohammed Shafi Shajakhan wrote: > From: Mohammed Shafi Shajakhan > > During firmware crash (or) user requested manual restart > the system gets into a soft lock up state because of the > below root cause. > > During user requested hardware restart / firmware crash > the system goes into a soft lockup state as 'napi_synchronize' > is called after 'napi_disable' (which sets 'NAPI_STATE_SCHED' > bit) and it sleeps into infinite loop as it waits for > 'NAPI_STATE_SCHED' to be cleared. This condition is hit because > 'ath10k_hif_stop' is called twice as below (resulting in calling > 'napi_synchronize' after 'napi_disable') > > 'ath10k_core_restart' -> 'ath10k_hif_stop' (ATH10K_STATE_ON) -> > -> 'ieee80211_restart_hw' -> 'ath10k_start' -> 'ath10k_halt' -> > 'ath10k_core_stop' -> 'ath10k_hif_stop' (ATH10K_STATE_RESTARTING) > > Fix this by calling 'ath10k_halt' in ath10k_core_restart itself > as it makes more sense before informing mac80211 to restart h/w > Also remove 'ath10k_halt' in ath10k_start for the state of 'restarting' > > Signed-off-by: Mohammed Shafi Shajakhan > --- > [thanks to Kalle and Michal for their inputs] > > drivers/net/wireless/ath/ath10k/core.c | 2 +- > drivers/net/wireless/ath/ath10k/mac.c | 1 - > 2 files changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c > index 7005e2a..5bc6847 100644 > --- a/drivers/net/wireless/ath/ath10k/core.c > +++ b/drivers/net/wireless/ath/ath10k/core.c > @@ -1536,7 +1536,7 @@ static void ath10k_core_restart(struct work_struct *work) > switch (ar->state) { > case ATH10K_STATE_ON: > ar->state = ATH10K_STATE_RESTARTING; > - ath10k_hif_stop(ar); > + ath10k_halt(ar); > ath10k_scan_finish(ar); > ieee80211_restart_hw(ar->hw); > break; > diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c > index 717b2fa..481842b 100644 > --- a/drivers/net/wireless/ath/ath10k/mac.c > +++ b/drivers/net/wireless/ath/ath10k/mac.c > @@ -4449,7 +4449,6 @@ static int ath10k_start(struct ieee80211_hw *hw) > ar->state = ATH10K_STATE_ON; > break; > case ATH10K_STATE_RESTARTING: > - ath10k_halt(ar); > ar->state = ATH10K_STATE_RESTARTED; > break; > case ATH10K_STATE_ON: > -- Ben Greear Candela Technologies Inc http://www.candelatech.com