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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 <greearb@candelatech.com>
Tested-by: Hun-Kyi Wynn <hkwynn@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Johannes Berg 14 年之前
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3207390a8b
共有 1 个文件被更改,包括 6 次插入6 次删除
  1. 6 6
      net/wireless/scan.c

+ 6 - 6
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);