Patch "mac80211: Fix possible sband related NULL pointer de-reference" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

mac80211: Fix possible sband related NULL pointer de-reference

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: mac80211-fix-possible-sband-related-null-pointer-de-reference.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Mar 22 14:40:23 CET 2018

From: Mohammed Shafi Shajakhan mohammed@qti.qualcomm.com Date: Thu, 27 Apr 2017 12:45:38 +0530 Subject: mac80211: Fix possible sband related NULL pointer de-reference

From: Mohammed Shafi Shajakhan mohammed@qti.qualcomm.com

[ Upstream commit 21a8e9dd52b64f0170bad208293ef8c30c3c1403 ]

Existing API 'ieee80211_get_sdata_band' returns default 2 GHz band even if the channel context configuration is NULL. This crashes for chipsets which support 5 Ghz alone when it tries to access members of 'sband'. Channel context configuration can be NULL in multivif case and when channel switch is in progress (or) when it fails. Fix this by replacing the API 'ieee80211_get_sdata_band' with 'ieee80211_get_sband' which returns a NULL pointer for sband when the channel configuration is NULL.

An example scenario is as below:

In multivif mode (AP + STA) with drivers like ath10k, when we do a channel switch in the AP vif (which has a number of clients connected) and a STA vif which is connected to some other AP, when the channel switch in AP vif fails, while the STA vifs tries to connect to the other AP, there is a window where the channel context is NULL/invalid and this results in a crash while the clients connected to the AP vif tries to reconnect and this race is very similar to the one investigated by Michal in https://patchwork.kernel.org/patch/3788161/ and this does happens with hardware that supports 5Ghz alone after long hours of testing with continuous channel switch on the AP vif

ieee80211 phy0: channel context reservation cannot be finalized because some interfaces aren't switching wlan0: failed to finalize CSA, disconnecting wlan0-1: deauthenticating from 8c:fd:f0:01:54:9c by local choice (Reason: 3=DEAUTH_LEAVING)

WARNING: CPU: 1 PID: 19032 at net/mac80211/ieee80211_i.h:1013 sta_info_alloc+0x374/0x3fc [mac80211] [<bf77272c>] (sta_info_alloc [mac80211]) [<bf78776c>] (ieee80211_add_station [mac80211])) [<bf73cc50>] (nl80211_new_station [cfg80211])

Unable to handle kernel NULL pointer dereference at virtual address 00000014 pgd = d5f4c000 Internal error: Oops: 17 [#1] PREEMPT SMP ARM PC is at sta_info_alloc+0x380/0x3fc [mac80211] LR is at sta_info_alloc+0x37c/0x3fc [mac80211] [<bf772738>] (sta_info_alloc [mac80211]) [<bf78776c>] (ieee80211_add_station [mac80211]) [<bf73cc50>] (nl80211_new_station [cfg80211]))

Cc: Michal Kazior michal.kazior@tieto.com Signed-off-by: Mohammed Shafi Shajakhan mohammed@qti.qualcomm.com Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mac80211/cfg.c | 30 +++++++++++++++++------------- net/mac80211/ibss.c | 6 +++++- net/mac80211/ieee80211_i.h | 36 +++++++++++++++++++++--------------- net/mac80211/mesh.c | 29 ++++++++++++++++++++--------- net/mac80211/mesh_plink.c | 37 ++++++++++++++++++++++++++----------- net/mac80211/mlme.c | 14 ++++++++++++-- net/mac80211/rate.c | 4 +++- net/mac80211/sta_info.c | 13 +++++++++---- net/mac80211/tdls.c | 29 +++++++++++++++++++---------- net/mac80211/tx.c | 5 ++++- net/mac80211/util.c | 6 +++--- 11 files changed, 139 insertions(+), 70 deletions(-)

--- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -620,10 +620,11 @@ void sta_set_rate_info_tx(struct sta_inf int shift = ieee80211_vif_get_shift(&sta->sdata->vif); u16 brate;

- sband = sta->local->hw.wiphy->bands[ - ieee80211_get_sdata_band(sta->sdata)]; - brate = sband->bitrates[rate->idx].bitrate; - rinfo->legacy = DIV_ROUND_UP(brate, 1 << shift); + sband = ieee80211_get_sband(sta->sdata); + if (sband) { + brate = sband->bitrates[rate->idx].bitrate; + rinfo->legacy = DIV_ROUND_UP(brate, 1 << shift); + } } if (rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) rinfo->bw = RATE_INFO_BW_40; @@ -1218,10 +1219,11 @@ static int sta_apply_parameters(struct i int ret = 0; struct ieee80211_supported_band *sband; struct ieee80211_sub_if_data *sdata = sta->sdata; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); u32 mask, set;

- sband = local->hw.wiphy->bands[band]; + sband = ieee80211_get_sband(sdata); + if (!sband) + return -EINVAL;

mask = params->sta_flags_mask; set = params->sta_flags_set; @@ -1354,7 +1356,7 @@ static int sta_apply_parameters(struct i ieee80211_parse_bitrates(&sdata->vif.bss_conf.chandef, sband, params->supported_rates, params->supported_rates_len, - &sta->sta.supp_rates[band]); + &sta->sta.supp_rates[sband->band]); }

if (params->ht_capa) @@ -1370,8 +1372,8 @@ static int sta_apply_parameters(struct i /* returned value is only needed for rc update, but the * rc isn't initialized here yet, so ignore it */ - __ieee80211_vht_handle_opmode(sdata, sta, - params->opmode_notif, band); + __ieee80211_vht_handle_opmode(sdata, sta, params->opmode_notif, + sband->band); }

if (params->support_p2p_ps >= 0) @@ -2017,13 +2019,15 @@ static int ieee80211_change_bss(struct w struct bss_parameters *params) { struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); - enum nl80211_band band; + struct ieee80211_supported_band *sband; u32 changed = 0;

if (!sdata_dereference(sdata->u.ap.beacon, sdata)) return -ENOENT;

- band = ieee80211_get_sdata_band(sdata); + sband = ieee80211_get_sband(sdata); + if (!sband) + return -EINVAL;

if (params->use_cts_prot >= 0) { sdata->vif.bss_conf.use_cts_prot = params->use_cts_prot; @@ -2036,7 +2040,7 @@ static int ieee80211_change_bss(struct w }

if (!sdata->vif.bss_conf.use_short_slot && - band == NL80211_BAND_5GHZ) { + sband->band == NL80211_BAND_5GHZ) { sdata->vif.bss_conf.use_short_slot = true; changed |= BSS_CHANGED_ERP_SLOT; } @@ -2049,7 +2053,7 @@ static int ieee80211_change_bss(struct w

if (params->basic_rates) { ieee80211_parse_bitrates(&sdata->vif.bss_conf.chandef, - wiphy->bands[band], + wiphy->bands[sband->band], params->basic_rates, params->basic_rates_len, &sdata->vif.bss_conf.basic_rates); --- a/net/mac80211/ibss.c +++ b/net/mac80211/ibss.c @@ -994,7 +994,7 @@ static void ieee80211_update_sta_info(st enum nl80211_band band = rx_status->band; enum nl80211_bss_scan_width scan_width; struct ieee80211_local *local = sdata->local; - struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band]; + struct ieee80211_supported_band *sband; bool rates_updated = false; u32 supp_rates = 0;

@@ -1004,6 +1004,10 @@ static void ieee80211_update_sta_info(st if (!ether_addr_equal(mgmt->bssid, sdata->u.ibss.bssid)) return;

+ sband = local->hw.wiphy->bands[band]; + if (WARN_ON(!sband)) + return; + rcu_read_lock(); sta = sta_info_get(sdata, mgmt->sa);

--- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -991,21 +991,6 @@ sdata_assert_lock(struct ieee80211_sub_i lockdep_assert_held(&sdata->wdev.mtx); }

-static inline enum nl80211_band -ieee80211_get_sdata_band(struct ieee80211_sub_if_data *sdata) -{ - enum nl80211_band band = NL80211_BAND_2GHZ; - struct ieee80211_chanctx_conf *chanctx_conf; - - rcu_read_lock(); - chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (!WARN_ON(!chanctx_conf)) - band = chanctx_conf->def.chan->band; - rcu_read_unlock(); - - return band; -} - static inline int ieee80211_chandef_get_shift(struct cfg80211_chan_def *chandef) { @@ -1410,6 +1395,27 @@ IEEE80211_WDEV_TO_SUB_IF(struct wireless return container_of(wdev, struct ieee80211_sub_if_data, wdev); }

+static inline struct ieee80211_supported_band * +ieee80211_get_sband(struct ieee80211_sub_if_data *sdata) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_chanctx_conf *chanctx_conf; + enum nl80211_band band; + + rcu_read_lock(); + chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); + + if (WARN_ON(!chanctx_conf)) { + rcu_read_unlock(); + return NULL; + } + + band = chanctx_conf->def.chan->band; + rcu_read_unlock(); + + return local->hw.wiphy->bands[band]; +} + /* this struct represents 802.11n's RA/TID combination */ struct ieee80211_ra_tid { u8 ra[ETH_ALEN]; --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -63,6 +63,7 @@ bool mesh_matches_local(struct ieee80211 struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; u32 basic_rates = 0; struct cfg80211_chan_def sta_chan_def; + struct ieee80211_supported_band *sband;

/* * As support for each feature is added, check for matching @@ -83,7 +84,11 @@ bool mesh_matches_local(struct ieee80211 (ifmsh->mesh_auth_id == ie->mesh_config->meshconf_auth))) return false;

- ieee80211_sta_get_rates(sdata, ie, ieee80211_get_sdata_band(sdata), + sband = ieee80211_get_sband(sdata); + if (!sband) + return false; + + ieee80211_sta_get_rates(sdata, ie, sband->band, &basic_rates);

if (sdata->vif.bss_conf.basic_rates != basic_rates) @@ -399,12 +404,13 @@ static int mesh_add_ds_params_ie(struct int mesh_add_ht_cap_ie(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) { - struct ieee80211_local *local = sdata->local; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); struct ieee80211_supported_band *sband; u8 *pos;

- sband = local->hw.wiphy->bands[band]; + sband = ieee80211_get_sband(sdata); + if (!sband) + return -EINVAL; + if (!sband->ht_cap.ht_supported || sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT || sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_5 || @@ -462,12 +468,13 @@ int mesh_add_ht_oper_ie(struct ieee80211 int mesh_add_vht_cap_ie(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) { - struct ieee80211_local *local = sdata->local; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); struct ieee80211_supported_band *sband; u8 *pos;

- sband = local->hw.wiphy->bands[band]; + sband = ieee80211_get_sband(sdata); + if (!sband) + return -EINVAL; + if (!sband->vht_cap.vht_supported || sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT || sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_5 || @@ -916,12 +923,16 @@ ieee80211_mesh_process_chnswitch(struct struct cfg80211_csa_settings params; struct ieee80211_csa_ie csa_ie; struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); + struct ieee80211_supported_band *sband; int err; u32 sta_flags;

sdata_assert_lock(sdata);

+ sband = ieee80211_get_sband(sdata); + if (!sband) + return false; + sta_flags = IEEE80211_STA_DISABLE_VHT; switch (sdata->vif.bss_conf.chandef.width) { case NL80211_CHAN_WIDTH_20_NOHT: @@ -935,7 +946,7 @@ ieee80211_mesh_process_chnswitch(struct

memset(&params, 0, sizeof(params)); memset(&csa_ie, 0, sizeof(csa_ie)); - err = ieee80211_parse_ch_switch_ie(sdata, elems, band, + err = ieee80211_parse_ch_switch_ie(sdata, elems, sband->band, sta_flags, sdata->vif.addr, &csa_ie); if (err < 0) --- a/net/mac80211/mesh_plink.c +++ b/net/mac80211/mesh_plink.c @@ -93,19 +93,23 @@ static inline void mesh_plink_fsm_restar static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata) { struct ieee80211_local *local = sdata->local; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); - struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band]; + struct ieee80211_supported_band *sband; struct sta_info *sta; u32 erp_rates = 0, changed = 0; int i; bool short_slot = false;

- if (band == NL80211_BAND_5GHZ) { + sband = ieee80211_get_sband(sdata); + if (!sband) + return changed; + + if (sband->band == NL80211_BAND_5GHZ) { /* (IEEE 802.11-2012 19.4.5) */ short_slot = true; goto out; - } else if (band != NL80211_BAND_2GHZ) + } else if (sband->band != NL80211_BAND_2GHZ) { goto out; + }

for (i = 0; i < sband->n_bitrates; i++) if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G) @@ -121,7 +125,7 @@ static u32 mesh_set_short_slot_time(stru continue;

short_slot = false; - if (erp_rates & sta->sta.supp_rates[band]) + if (erp_rates & sta->sta.supp_rates[sband->band]) short_slot = true; else break; @@ -247,7 +251,15 @@ static int mesh_plink_frame_tx(struct ie mgmt->u.action.u.self_prot.action_code = action;

if (action != WLAN_SP_MESH_PEERING_CLOSE) { - enum nl80211_band band = ieee80211_get_sdata_band(sdata); + struct ieee80211_supported_band *sband; + enum nl80211_band band; + + sband = ieee80211_get_sband(sdata); + if (!sband) { + err = -EINVAL; + goto free; + } + band = sband->band;

/* capability info */ pos = skb_put(skb, 2); @@ -393,13 +405,16 @@ static void mesh_sta_info_init(struct ie struct ieee802_11_elems *elems, bool insert) { struct ieee80211_local *local = sdata->local; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); struct ieee80211_supported_band *sband; u32 rates, basic_rates = 0, changed = 0; enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;

- sband = local->hw.wiphy->bands[band]; - rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates); + sband = ieee80211_get_sband(sdata); + if (!sband) + return; + + rates = ieee80211_sta_get_rates(sdata, elems, sband->band, + &basic_rates);

spin_lock_bh(&sta->mesh->plink_lock); sta->rx_stats.last_rx = jiffies; @@ -410,9 +425,9 @@ static void mesh_sta_info_init(struct ie goto out; sta->mesh->processed_beacon = true;

- if (sta->sta.supp_rates[band] != rates) + if (sta->sta.supp_rates[sband->band] != rates) changed |= IEEE80211_RC_SUPP_RATES_CHANGED; - sta->sta.supp_rates[band] = rates; + sta->sta.supp_rates[sband->band] = rates;

if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband, elems->ht_cap_elem, sta)) --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1851,11 +1851,16 @@ static u32 ieee80211_handle_bss_capabili u16 capab, bool erp_valid, u8 erp) { struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf; + struct ieee80211_supported_band *sband; u32 changed = 0; bool use_protection; bool use_short_preamble; bool use_short_slot;

+ sband = ieee80211_get_sband(sdata); + if (!sband) + return changed; + if (erp_valid) { use_protection = (erp & WLAN_ERP_USE_PROTECTION) != 0; use_short_preamble = (erp & WLAN_ERP_BARKER_PREAMBLE) == 0; @@ -1865,7 +1870,7 @@ static u32 ieee80211_handle_bss_capabili }

use_short_slot = !!(capab & WLAN_CAPABILITY_SHORT_SLOT_TIME); - if (ieee80211_get_sdata_band(sdata) == NL80211_BAND_5GHZ) + if (sband->band == NL80211_BAND_5GHZ) use_short_slot = true;

if (use_protection != bss_conf->use_cts_prot) { @@ -2994,7 +2999,12 @@ static bool ieee80211_assoc_success(stru goto out; }

- sband = local->hw.wiphy->bands[ieee80211_get_sdata_band(sdata)]; + sband = ieee80211_get_sband(sdata); + if (!sband) { + mutex_unlock(&sdata->local->sta_mtx); + ret = false; + goto out; + }

/* Set up internal HT/VHT capabilities */ if (elems.ht_cap_elem && !(ifmgd->flags & IEEE80211_STA_DISABLE_HT)) --- a/net/mac80211/rate.c +++ b/net/mac80211/rate.c @@ -875,7 +875,9 @@ int rate_control_set_rates(struct ieee80 struct ieee80211_sta_rates *old; struct ieee80211_supported_band *sband;

- sband = hw->wiphy->bands[ieee80211_get_sdata_band(sta->sdata)]; + sband = ieee80211_get_sband(sta->sdata); + if (!sband) + return -EINVAL; rate_control_apply_mask_ratetbl(sta, sband, rates); /* * mac80211 guarantees that this function will not be called --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -395,10 +395,15 @@ struct sta_info *sta_info_alloc(struct i sta->sta.smps_mode = IEEE80211_SMPS_OFF; if (sdata->vif.type == NL80211_IFTYPE_AP || sdata->vif.type == NL80211_IFTYPE_AP_VLAN) { - struct ieee80211_supported_band *sband = - hw->wiphy->bands[ieee80211_get_sdata_band(sdata)]; - u8 smps = (sband->ht_cap.cap & IEEE80211_HT_CAP_SM_PS) >> - IEEE80211_HT_CAP_SM_PS_SHIFT; + struct ieee80211_supported_band *sband; + u8 smps; + + sband = ieee80211_get_sband(sdata); + if (!sband) + goto free_txq; + + smps = (sband->ht_cap.cap & IEEE80211_HT_CAP_SM_PS) >> + IEEE80211_HT_CAP_SM_PS_SHIFT; /* * Assume that hostapd advertises our caps in the beacon and * this is the known_smps_mode for a station that just assciated --- a/net/mac80211/tdls.c +++ b/net/mac80211/tdls.c @@ -47,8 +47,7 @@ static void ieee80211_tdls_add_ext_capab NL80211_FEATURE_TDLS_CHANNEL_SWITCH; bool wider_band = ieee80211_hw_check(&local->hw, TDLS_WIDER_BW) && !ifmgd->tdls_wider_bw_prohibited; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); - struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band]; + struct ieee80211_supported_band *sband = ieee80211_get_sband(sdata); bool vht = sband && sband->vht_cap.vht_supported; u8 *pos = (void *)skb_put(skb, 10);

@@ -180,11 +179,14 @@ static void ieee80211_tdls_add_bss_coex_ static u16 ieee80211_get_tdls_sta_capab(struct ieee80211_sub_if_data *sdata, u16 status_code) { + struct ieee80211_supported_band *sband; + /* The capability will be 0 when sending a failure code */ if (status_code != 0) return 0;

- if (ieee80211_get_sdata_band(sdata) == NL80211_BAND_2GHZ) { + sband = ieee80211_get_sband(sdata); + if (sband && sband->band == NL80211_BAND_2GHZ) { return WLAN_CAPABILITY_SHORT_SLOT_TIME | WLAN_CAPABILITY_SHORT_PREAMBLE; } @@ -358,17 +360,20 @@ ieee80211_tdls_add_setup_start_ies(struc u8 action_code, bool initiator, const u8 *extra_ies, size_t extra_ies_len) { - enum nl80211_band band = ieee80211_get_sdata_band(sdata); - struct ieee80211_local *local = sdata->local; struct ieee80211_supported_band *sband; + struct ieee80211_local *local = sdata->local; struct ieee80211_sta_ht_cap ht_cap; struct ieee80211_sta_vht_cap vht_cap; struct sta_info *sta = NULL; size_t offset = 0, noffset; u8 *pos;

- ieee80211_add_srates_ie(sdata, skb, false, band); - ieee80211_add_ext_srates_ie(sdata, skb, false, band); + sband = ieee80211_get_sband(sdata); + if (!sband) + return; + + ieee80211_add_srates_ie(sdata, skb, false, sband->band); + ieee80211_add_ext_srates_ie(sdata, skb, false, sband->band); ieee80211_tdls_add_supp_channels(sdata, skb);

/* add any custom IEs that go before Extended Capabilities */ @@ -439,7 +444,6 @@ ieee80211_tdls_add_setup_start_ies(struc * the same on all bands. The specification limits the setup to a * single HT-cap, so use the current band for now. */ - sband = local->hw.wiphy->bands[band]; memcpy(&ht_cap, &sband->ht_cap, sizeof(ht_cap));

if ((action_code == WLAN_TDLS_SETUP_REQUEST || @@ -545,9 +549,13 @@ ieee80211_tdls_add_setup_cfm_ies(struct struct ieee80211_if_managed *ifmgd = &sdata->u.mgd; size_t offset = 0, noffset; struct sta_info *sta, *ap_sta; - enum nl80211_band band = ieee80211_get_sdata_band(sdata); + struct ieee80211_supported_band *sband; u8 *pos;

+ sband = ieee80211_get_sband(sdata); + if (!sband) + return; + mutex_lock(&local->sta_mtx);

sta = sta_info_get(sdata, peer); @@ -612,7 +620,8 @@ ieee80211_tdls_add_setup_cfm_ies(struct ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);

/* only include VHT-operation if not on the 2.4GHz band */ - if (band != NL80211_BAND_2GHZ && sta->sta.vht_cap.vht_supported) { + if (sband->band != NL80211_BAND_2GHZ && + sta->sta.vht_cap.vht_supported) { /* * if both peers support WIDER_BW, we can expand the chandef to * a wider compatible one, up to 80MHz --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -4182,7 +4182,10 @@ struct sk_buff *ieee80211_beacon_get_tim return bcn;

shift = ieee80211_vif_get_shift(vif); - sband = hw->wiphy->bands[ieee80211_get_sdata_band(vif_to_sdata(vif))]; + sband = ieee80211_get_sband(vif_to_sdata(vif)); + if (!sband) + return bcn; + ieee80211_tx_monitor(hw_to_local(hw), copy, sband, 1, shift, false);

return bcn; --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -1590,14 +1590,14 @@ u32 ieee80211_sta_get_rates(struct ieee8 size_t num_rates; u32 supp_rates, rate_flags; int i, j, shift; + sband = sdata->local->hw.wiphy->bands[band]; + if (WARN_ON(!sband)) + return 1;

rate_flags = ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef); shift = ieee80211_vif_get_shift(&sdata->vif);

- if (WARN_ON(!sband)) - return 1; - num_rates = sband->n_bitrates; supp_rates = 0; for (i = 0; i < elems->supp_rates_len +

Patches currently in stable-queue which might be from mohammed@qti.qualcomm.com are

queue-4.9/mac80211-fix-possible-sband-related-null-pointer-de-reference.patch queue-4.9/ath-fix-updating-radar-flags-for-coutry-code-india.patch