mac80211 handles roc expirations (indicated by ieee80211_remain_on_channel_expired()) with a separate work (hw_roc_done).
If userspace asks to cancel the ongoing roc before hw_roc_done was scheduled, mac80211 will cancel the ongoing roc, while leaving the hw_roc_done work pending. This might end up in the next roc being cancelled by the stale work, causing mac80211 and the low-level driver to go out of sync. Fix it by cancelling hw_roc_done on roc cancel. Since hw_roc_done takes local->mtx, temporarily release it (before re-acquiring it and starting the next roc if needed). Signed-off-by: Eliad Peller <[email protected]> --- net/mac80211/cfg.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index dd4ff36..a80f7b3 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -2782,7 +2782,22 @@ static int ieee80211_cancel_roc(struct ieee80211_local *local, } list_del(&found->list); + mutex_unlock(&local->mtx); + + /* + * The driver might have already expired the ROC (by + * calling ieee80211_remain_on_channel_expired()), so + * cancel the pending roc_done work (otherwise, it might + * cancel the upcoming roc). + */ + cancel_work_sync(&local->hw_roc_done); + mutex_lock(&local->mtx); + /* + * We hold rtnl, so nothing should have been able to + * manipulate the roc_list during the temporary + * lock release. + */ if (found->started) ieee80211_start_next_roc(local); mutex_unlock(&local->mtx); -- 1.8.5.2.229.g4448466.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
