From 3fbd45ca8d1c98f3c2582ef8bc70ade42f70947b Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 25 Mar 2013 11:51:14 +0100 Subject: [PATCH 1/2] mac80211: fix remain-on-channel cancel crash If a ROC item is canceled just as it expires, the work struct may be scheduled while it is running (and waiting for the mutex). This results in it being run after being freed, which obviously crashes. To fix this don't free it when aborting is requested but instead mark it as "to be freed", which makes the work a no-op and allows freeing it outside. Cc: stable@vger.kernel.org [3.6+] Reported-by: Jouni Malinen Tested-by: Jouni Malinen Signed-off-by: Johannes Berg --- net/mac80211/cfg.c | 6 ++++-- net/mac80211/ieee80211_i.h | 3 ++- net/mac80211/offchannel.c | 23 +++++++++++++++++------ 3 files changed, 23 insertions(+), 9 deletions(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index fb306814576a..a6893602f87a 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -2582,7 +2582,7 @@ static int ieee80211_cancel_roc(struct ieee80211_local *local, list_del(&dep->list); mutex_unlock(&local->mtx); - ieee80211_roc_notify_destroy(dep); + ieee80211_roc_notify_destroy(dep, true); return 0; } @@ -2622,7 +2622,7 @@ static int ieee80211_cancel_roc(struct ieee80211_local *local, ieee80211_start_next_roc(local); mutex_unlock(&local->mtx); - ieee80211_roc_notify_destroy(found); + ieee80211_roc_notify_destroy(found, true); } else { /* work may be pending so use it all the time */ found->abort = true; @@ -2632,6 +2632,8 @@ static int ieee80211_cancel_roc(struct ieee80211_local *local, /* work will clean up etc */ flush_delayed_work(&found->work); + WARN_ON(!found->to_be_freed); + kfree(found); } return 0; diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 388580a1bada..7bdefd901f9d 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -309,6 +309,7 @@ struct ieee80211_roc_work { struct ieee80211_channel *chan; bool started, abort, hw_begun, notified; + bool to_be_freed; unsigned long hw_start_time; @@ -1347,7 +1348,7 @@ void ieee80211_offchannel_return(struct ieee80211_local *local); void ieee80211_roc_setup(struct ieee80211_local *local); void ieee80211_start_next_roc(struct ieee80211_local *local); void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata); -void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc); +void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free); void ieee80211_sw_roc_work(struct work_struct *work); void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc); diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c index cc79b4a2e821..430bd254e496 100644 --- a/net/mac80211/offchannel.c +++ b/net/mac80211/offchannel.c @@ -297,10 +297,13 @@ void ieee80211_start_next_roc(struct ieee80211_local *local) } } -void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc) +void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free) { struct ieee80211_roc_work *dep, *tmp; + if (WARN_ON(roc->to_be_freed)) + return; + /* was never transmitted */ if (roc->frame) { cfg80211_mgmt_tx_status(&roc->sdata->wdev, @@ -316,9 +319,12 @@ void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc) GFP_KERNEL); list_for_each_entry_safe(dep, tmp, &roc->dependents, list) - ieee80211_roc_notify_destroy(dep); + ieee80211_roc_notify_destroy(dep, true); - kfree(roc); + if (free) + kfree(roc); + else + roc->to_be_freed = true; } void ieee80211_sw_roc_work(struct work_struct *work) @@ -331,6 +337,9 @@ void ieee80211_sw_roc_work(struct work_struct *work) mutex_lock(&local->mtx); + if (roc->to_be_freed) + goto out_unlock; + if (roc->abort) goto finish; @@ -370,7 +379,7 @@ void ieee80211_sw_roc_work(struct work_struct *work) finish: list_del(&roc->list); started = roc->started; - ieee80211_roc_notify_destroy(roc); + ieee80211_roc_notify_destroy(roc, !roc->abort); if (started) { drv_flush(local, false); @@ -410,7 +419,7 @@ static void ieee80211_hw_roc_done(struct work_struct *work) list_del(&roc->list); - ieee80211_roc_notify_destroy(roc); + ieee80211_roc_notify_destroy(roc, true); /* if there's another roc, start it now */ ieee80211_start_next_roc(local); @@ -460,12 +469,14 @@ void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata) list_for_each_entry_safe(roc, tmp, &tmp_list, list) { if (local->ops->remain_on_channel) { list_del(&roc->list); - ieee80211_roc_notify_destroy(roc); + ieee80211_roc_notify_destroy(roc, true); } else { ieee80211_queue_delayed_work(&local->hw, &roc->work, 0); /* work will clean up etc */ flush_delayed_work(&roc->work); + WARN_ON(!roc->to_be_freed); + kfree(roc); } } From 382a103b2b528a3085cde4ac56fc69d92a828b72 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 22 Mar 2013 22:30:09 +0100 Subject: [PATCH 2/2] mac80211: fix idle handling sequence Corey Richardson reported that my idle handling cleanup (commit fd0f979a1b, "mac80211: simplify idle handling") broke ath9k_htc. The reason appears to be that it wants to go out of idle before switching channels. To fix it, reimplement that sequence. Reported-by: Corey Richardson Signed-off-by: Johannes Berg --- net/mac80211/chan.c | 17 ++++++++++++++--- net/mac80211/ieee80211_i.h | 1 + net/mac80211/iface.c | 2 +- 3 files changed, 16 insertions(+), 4 deletions(-) diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 78c0d90dd641..931be419ab5a 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -63,6 +63,7 @@ ieee80211_new_chanctx(struct ieee80211_local *local, enum ieee80211_chanctx_mode mode) { struct ieee80211_chanctx *ctx; + u32 changed; int err; lockdep_assert_held(&local->chanctx_mtx); @@ -76,6 +77,13 @@ ieee80211_new_chanctx(struct ieee80211_local *local, ctx->conf.rx_chains_dynamic = 1; ctx->mode = mode; + /* acquire mutex to prevent idle from changing */ + mutex_lock(&local->mtx); + /* turn idle off *before* setting channel -- some drivers need that */ + changed = ieee80211_idle_off(local); + if (changed) + ieee80211_hw_config(local, changed); + if (!local->use_chanctx) { local->_oper_channel_type = cfg80211_get_chandef_type(chandef); @@ -85,14 +93,17 @@ ieee80211_new_chanctx(struct ieee80211_local *local, err = drv_add_chanctx(local, ctx); if (err) { kfree(ctx); - return ERR_PTR(err); + ctx = ERR_PTR(err); + + ieee80211_recalc_idle(local); + goto out; } } + /* and keep the mutex held until the new chanctx is on the list */ list_add_rcu(&ctx->list, &local->chanctx_list); - mutex_lock(&local->mtx); - ieee80211_recalc_idle(local); + out: mutex_unlock(&local->mtx); return ctx; diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 7bdefd901f9d..5672533a0832 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1362,6 +1362,7 @@ int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata, enum nl80211_iftype type); void ieee80211_if_remove(struct ieee80211_sub_if_data *sdata); void ieee80211_remove_interfaces(struct ieee80211_local *local); +u32 ieee80211_idle_off(struct ieee80211_local *local); void ieee80211_recalc_idle(struct ieee80211_local *local); void ieee80211_adjust_monitor_flags(struct ieee80211_sub_if_data *sdata, const int offset); diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 3bfe2612c8c2..58150f877ec3 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -78,7 +78,7 @@ void ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata) ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_TXPOWER); } -static u32 ieee80211_idle_off(struct ieee80211_local *local) +u32 ieee80211_idle_off(struct ieee80211_local *local) { if (!(local->hw.conf.flags & IEEE80211_CONF_IDLE)) return 0;