diff options
Diffstat (limited to 'package/kernel/mac80211/patches/390-mac80211-fix-a-race-between-restart-and-CSA-flows.patch')
| -rw-r--r-- | package/kernel/mac80211/patches/390-mac80211-fix-a-race-between-restart-and-CSA-flows.patch | 86 |
1 files changed, 0 insertions, 86 deletions
diff --git a/package/kernel/mac80211/patches/390-mac80211-fix-a-race-between-restart-and-CSA-flows.patch b/package/kernel/mac80211/patches/390-mac80211-fix-a-race-between-restart-and-CSA-flows.patch deleted file mode 100644 index db2aa0443f..0000000000 --- a/package/kernel/mac80211/patches/390-mac80211-fix-a-race-between-restart-and-CSA-flows.patch +++ /dev/null @@ -1,86 +0,0 @@ -From: Emmanuel Grumbach <emmanuel.grumbach@intel.com> -Date: Fri, 31 Aug 2018 11:31:06 +0300 -Subject: [PATCH] mac80211: fix a race between restart and CSA flows - -We hit a problem with iwlwifi that was caused by a bug in -mac80211. A bug in iwlwifi caused the firwmare to crash in -certain cases in channel switch. Because of that bug, -drv_pre_channel_switch would fail and trigger the restart -flow. -Now we had the hw restart worker which runs on the system's -workqueue and the csa_connection_drop_work worker that runs -on mac80211's workqueue that can run together. This is -obviously problematic since the restart work wants to -reconfigure the connection, while the csa_connection_drop_work -worker does the exact opposite: it tries to disconnect. - -Fix this by cancelling the csa_connection_drop_work worker -in the restart worker. - -Note that this can sound racy: we could have: - -driver iface_work CSA_work restart_work -+++++++++++++++++++++++++++++++++++++++++++++ - | - <--drv_cs ---| -<FW CRASH!> --CS FAILED--> - | | - | cancel_work(CSA) - schedule | - CSA work | - | | - Race between those 2 - -But this is not possible because we flush the workqueue -in the restart worker before we cancel the CSA worker. -That would be bullet proof if we could guarantee that -we schedule the CSA worker only from the iface_work -which runs on the workqueue (and not on the system's -workqueue), but unfortunately we do have an instance -in which we schedule the CSA work outside the context -of the workqueue (ieee80211_chswitch_done). - -Note also that we should probably cancel other workers -like beacon_connection_loss_work and possibly others -for different types of interfaces, at the very least, -IBSS should suffer from the exact same problem, but for -now, do the minimum to fix the actual bug that was actually -experienced and reproduced. - -Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> -Signed-off-by: Luca Coelho <luciano.coelho@intel.com> -Signed-off-by: Johannes Berg <johannes.berg@intel.com> ---- - ---- a/net/mac80211/main.c -+++ b/net/mac80211/main.c -@@ -255,8 +255,27 @@ static void ieee80211_restart_work(struc - - flush_work(&local->radar_detected_work); - rtnl_lock(); -- list_for_each_entry(sdata, &local->interfaces, list) -+ list_for_each_entry(sdata, &local->interfaces, list) { -+ /* -+ * XXX: there may be more work for other vif types and even -+ * for station mode: a good thing would be to run most of -+ * the iface type's dependent _stop (ieee80211_mg_stop, -+ * ieee80211_ibss_stop) etc... -+ * For now, fix only the specific bug that was seen: race -+ * between csa_connection_drop_work and us. -+ */ -+ if (sdata->vif.type == NL80211_IFTYPE_STATION) { -+ /* -+ * This worker is scheduled from the iface worker that -+ * runs on mac80211's workqueue, so we can't be -+ * scheduling this worker after the cancel right here. -+ * The exception is ieee80211_chswitch_done. -+ * Then we can have a race... -+ */ -+ cancel_work_sync(&sdata->u.mgd.csa_connection_drop_work); -+ } - flush_delayed_work(&sdata->dec_tailroom_needed_wk); -+ } - ieee80211_scan_cancel(local); - - /* make sure any new ROC will consider local->in_reconfig */ |