Return-path: Received: from mail-oi0-f48.google.com ([209.85.218.48]:35156 "EHLO mail-oi0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079AbaL0Si0 (ORCPT ); Sat, 27 Dec 2014 13:38:26 -0500 Received: by mail-oi0-f48.google.com with SMTP id u20so25154553oif.7 for ; Sat, 27 Dec 2014 10:38:25 -0800 (PST) Message-ID: <549EFC9F.9030504@lwfinger.net> (sfid-20141227_193830_072466_B4B82861) Date: Sat, 27 Dec 2014 12:38:23 -0600 From: Larry Finger MIME-Version: 1.0 To: Christian Lamparter , Christopher Chavez CC: linux-wireless@vger.kernel.org, Johannes Berg Subject: Re: p54usb kernel panic on recent mainline kernels References: <2296382.VCr2c4tJc9@debian64> <5946673.YueIgFzjsn@debian64> In-Reply-To: <5946673.YueIgFzjsn@debian64> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/27/2014 05:57 AM, Christian Lamparter wrote: > Alright, here's lunch [for the people in CET]. > > On Saturday, December 27, 2014 11:10:16 AM Christian Lamparter wrote: >> On Saturday, December 27, 2014 12:15:58 AM Christopher Chavez wrote: >>>> My bisection led to a branch commit d17ec4d as the "bad" commit. >>>> Rather than finding out where the bisection went bad, I added >>>> code to check skb->tail, skb->end, and the length to be added. >>>> At the time of the call that panics, there are 6 bytes between >>>> tail and end with 8 bytes needed. >>>> >>>> I will be looking for the place where the driver calculates how >>>> large the skb should be. >> >> From looking at a other patch from that time and context. I think: " >> >> commit ca34e3b5c808385b175650605faa29e71e91991b >> Author: Ido Yariv >> Date: Tue Jul 29 15:38:53 2014 +0300 >> >> mac80211: Fix accounting of the tailroom-needed counter [1] >> >> [...] >> I can think of several ways of dealing with this issue: >> >> 2. add extra IEEE80211_KEY_FLAG_ or HW_FLAG to restore the old behavior. >> This should be possible and relatively simple. But we/I have to be >> especially careful to differentiate properly between the old and new. >> [i.e.: I need to know what the deal is behind: >> IEEE80211_KEY_FLAG_GENERATE_IV_MGMT in this case? Looks like it can >> be ignored?] >> > > --- > [Note: for convenience this patch is rolled into one for now - > if it and the concept works, I'll make two parts. one for p54 > one for mac80211 [both -stable]. It would be great if someone > could proofread the commit message though - and provide > "tested-by" tags if possible] > > mac80211: re-enable tailroom resizing when needed for hardware encryption > > The patch "mac80211: Fix accounting of the tailroom-needed counter" reduced > the overhead associated with unnecessary resizing of outgoing frames. > Unfortunately this change broke the assumption that there is always enough > tailroom and this in turn caused p54* to panic. > > Reported-by: Christopher Chavez > Signed-off-by: Christian Lamparter > --- > diff --git a/drivers/net/wireless/p54/main.c b/drivers/net/wireless/p54/main.c > index 97aeff0..b877c7f 100644 > --- a/drivers/net/wireless/p54/main.c > +++ b/drivers/net/wireless/p54/main.c > @@ -751,6 +751,7 @@ struct ieee80211_hw *p54_init_common(size_t priv_data_len) > IEEE80211_HW_SUPPORTS_PS | > IEEE80211_HW_PS_NULLFUNC_STACK | > IEEE80211_HW_MFP_CAPABLE | > + IEEE80211_HW_TAILROOM_CRYPTO | > IEEE80211_HW_REPORTS_TX_ACK_STATUS; > > dev->wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION) | > diff --git a/include/net/mac80211.h b/include/net/mac80211.h > index 58d719d..c04ac04 100644 > --- a/include/net/mac80211.h > +++ b/include/net/mac80211.h > @@ -1270,8 +1270,11 @@ struct ieee80211_vif *wdev_to_ieee80211_vif(struct wireless_dev *wdev); > * > * @IEEE80211_KEY_FLAG_GENERATE_IV: This flag should be set by the > * driver to indicate that it requires IV generation for this > - * particular key. Setting this flag does not necessarily mean that SKBs > - * will have sufficient tailroom for ICV or MIC. > + * particular key. Setting this flag does not mean that SKBs will > + * have sufficient tailroom for ICV or MIC. If additional tailroom > + * tailroom needs to be reserved for the ICV or MIC, the driver > + * should also set the hardware feature flag: > + * %IEEE80211_HW_TAILROOM_CRYPTO. > * @IEEE80211_KEY_FLAG_GENERATE_MMIC: This flag should be set by > * the driver for a TKIP key if it requires Michael MIC > * generation in software. > @@ -1583,6 +1586,10 @@ struct ieee80211_tx_control { > * @IEEE80211_HW_MFP_CAPABLE: > * Hardware supports management frame protection (MFP, IEEE 802.11w). > * > + * @IEEE80211_HW_TAILROOM_CRYPTO: The driver would like to have sufficient > + * tailroom for ICV or MIC for outgoing frames in order to perform > + * hardware encryption without any additional resizing overhead. > + * > * @IEEE80211_HW_SUPPORTS_UAPSD: > * Hardware supports Unscheduled Automatic Power Save Delivery > * (U-APSD) in managed mode. The mode is configured with > @@ -1673,7 +1680,7 @@ enum ieee80211_hw_flags { > IEEE80211_HW_MFP_CAPABLE = 1<<13, > IEEE80211_HW_WANT_MONITOR_VIF = 1<<14, > IEEE80211_HW_NO_AUTO_VIF = 1<<15, > - /* free slot */ > + IEEE80211_HW_TAILROOM_CRYPTO = 1<<16, > IEEE80211_HW_SUPPORTS_UAPSD = 1<<17, > IEEE80211_HW_REPORTS_TX_ACK_STATUS = 1<<18, > IEEE80211_HW_CONNECTION_MONITOR = 1<<19, > diff --git a/net/mac80211/key.c b/net/mac80211/key.c > index 0bb7038..c3e9a9a 100644 > --- a/net/mac80211/key.c > +++ b/net/mac80211/key.c > @@ -140,7 +140,8 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key) > if (!ret) { > key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE; > > - if (!(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) > + if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) || > + (key->local->hw.flags & IEEE80211_HW_TAILROOM_CRYPTO))) > sdata->crypto_tx_tailroom_needed_cnt--; > > WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) && > @@ -188,7 +189,8 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key) > sta = key->sta; > sdata = key->sdata; > > - if (!(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) > + if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) || > + (key->local->hw.flags & IEEE80211_HW_TAILROOM_CRYPTO))) > increment_tailroom_need_count(sdata); > > ret = drv_set_key(key->local, DISABLE_KEY, sdata, > @@ -884,7 +886,8 @@ void ieee80211_remove_key(struct ieee80211_key_conf *keyconf) > if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) { > key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE; > > - if (!(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) > + if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) || > + (key->local->hw.flags & IEEE80211_HW_TAILROOM_CRYPTO))) > increment_tailroom_need_count(key->sdata); > } Christian, I had redone the bisection and found that ca34e3b was the bad commit. That was late last night (CST - UTC-5). I was pleased to find your patch in my mailbox this morning. With your patch, my system has survived for about 2 hours, whereas it would have failed in 2 minutes or less. You can add Tested-by: Larry Finger I think this needs to be applied to 3.{17-19}. Thanks, Larry