From: Johannes Berg Date: Wed, 6 Oct 2010 19:18:04 +0000 (+0200) Subject: cfg80211: fix BSS double-unlinking X-Git-Tag: firefly_0821_release~7613^2~3670^2~78^2^2~113 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3207390a8b58bfc1335750f91cf6783c48ca19ca;p=firefly-linux-kernel-4.4.55.git cfg80211: fix BSS double-unlinking When multiple interfaces are actively trying to associate with the same BSS, they may both find that the BSS isn't there and then try to unlink it. This can cause errors since the unlinking code can't currently deal with items that have already been unlinked. Normally this doesn't happen as most people don't try to use multiple station interfaces that associate at the same time too. Fix this by using the list entry as a flag to see if the item is still on a list. Cc: stable@kernel.org Reported-by: Ben Greear Tested-by: Hun-Kyi Wynn Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 5ca8c7180141..503ebb86ba18 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -650,14 +650,14 @@ void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub) bss = container_of(pub, struct cfg80211_internal_bss, pub); spin_lock_bh(&dev->bss_lock); + if (!list_empty(&bss->list)) { + list_del_init(&bss->list); + dev->bss_generation++; + rb_erase(&bss->rbn, &dev->bss_tree); - list_del(&bss->list); - dev->bss_generation++; - rb_erase(&bss->rbn, &dev->bss_tree); - + kref_put(&bss->ref, bss_release); + } spin_unlock_bh(&dev->bss_lock); - - kref_put(&bss->ref, bss_release); } EXPORT_SYMBOL(cfg80211_unlink_bss);