| From | Andi Kleen <> | Subject | [PATCH] [10/223] cfg80211: fix BSS double-unlinking | Date | Mon, 13 Dec 2010 00:45:05 +0100 (CET) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Johannes Berg <johannes.berg@intel.com>
commit 3207390a8b58bfc1335750f91cf6783c48ca19ca upstream.
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.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- net/wireless/scan.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
Index: linux/net/wireless/scan.c =================================================================== --- linux.orig/net/wireless/scan.c +++ linux/net/wireless/scan.c @@ -650,14 +650,14 @@ void cfg80211_unlink_bss(struct wiphy *w 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);
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