From 8301e613655c2d95fa5430a1a57d92d966fdc70b Mon Sep 17 00:00:00 2001 From: Vittorio Gambaletta Date: Tue, 14 Mar 2017 14:45:15 +0100 Subject: [PATCH] mac80211: Fix race condition leading to wifi interfaces not coming up at boot sometimes. In the drv_mac80211_setup function, mac80211_interface_cleanup is called to ask the kernel to delete all existing interfaces for the phy that is being configured via netlink. Later in the first function, mac80211_prepare_vif is called to set up the new interfaces as required. But sometimes, when mac80211_prepare_vif (and so the relevant `iw phy x interface add y` command) runs, the kernel might still be cleaning up the old interface with the same ifname. It usually takes very few time to do that; possibly a few milliseconds of sleep in the script after detecting this error condition could be enough, but the busybox sh does not support sub-second sleep intervals. When this happens, iw obviously fails to create the new interface; and the following message is printed in the system log, followed by subsequent failure messages from hostapd in case this would have been an AP interface. Tue Mar 14 04:21:57 2017 daemon.notice netifd: radio1 (2767): command failed: Too many open files in system (-23) This was a long-standing issue existing since at least OpenWrt Backfire, and today I finally managed to debug and (hopefully) solve it. It was happening very few times on most devices; but it was happening a lot more frequently on fast platforms with multiple radios, such as the powerpc-based dual-ath9k-radio tl-wdr4900-v1. Signed-off-by: Vittorio Gambaletta --- .../files/lib/netifd/wireless/mac80211.sh | 32 ++++++++++++++++--- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh index baa023ecf6..9ebd76be49 100644 --- a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh +++ b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh @@ -411,6 +411,28 @@ mac80211_check_ap() { has_ap=1 } +mac80211_iw_interface_add() { + local phy="$1" + local ifname="$2" + local type="$3" + local wdsflag="$4" + local rc + + iw phy "$phy" interface add "$ifname" type "$type" $wdsflag + rc="$?" + + [ "$rc" = 233 ] && { + # Device might have just been deleted, give the kernel some time to finish cleaning it up + sleep 1 + + iw phy "$phy" interface add "$ifname" type "$type" $wdsflag + rc="$?" + } + + [ "$rc" != 0 ] && wireless_setup_failed INTERFACE_CREATION_FAILED + return $rc +} + mac80211_prepare_vif() { json_select config @@ -437,7 +459,7 @@ mac80211_prepare_vif() { # It is far easier to delete and create the desired interface case "$mode" in adhoc) - iw phy "$phy" interface add "$ifname" type adhoc + mac80211_iw_interface_add "$phy" "$ifname" adhoc || return ;; ap) # Hostapd will handle recreating the interface and @@ -451,21 +473,21 @@ mac80211_prepare_vif() { mac80211_hostapd_setup_bss "$phy" "$ifname" "$macaddr" "$type" || return [ -n "$hostapd_ctrl" ] || { - iw phy "$phy" interface add "$ifname" type __ap + mac80211_iw_interface_add "$phy" "$ifname" __ap || return hostapd_ctrl="${hostapd_ctrl:-/var/run/hostapd/$ifname}" } ;; mesh) - iw phy "$phy" interface add "$ifname" type mp + mac80211_iw_interface_add "$phy" "$ifname" mp || return ;; monitor) - iw phy "$phy" interface add "$ifname" type monitor + mac80211_iw_interface_add "$phy" "$ifname" monitor || return ;; sta) local wdsflag= staidx="$(($staidx + 1))" [ "$wds" -gt 0 ] && wdsflag="4addr on" - iw phy "$phy" interface add "$ifname" type managed $wdsflag + mac80211_iw_interface_add "$phy" "$ifname" managed "$wdsflag" || return [ "$powersave" -gt 0 ] && powersave="on" || powersave="off" iw "$ifname" set power_save "$powersave" ;; -- 2.25.1