3.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
commit 499218595a2e8296b7492af32fcca141b7b8184a upstream.
Some mlme work structs are not cancelled on disassociation
nor interface deletion, which leads to them running after
the memory has been freed
There is not a clean way to cancel these in the disassociation
logic because they must be canceled outside of the ifmgd->mtx
lock, so just cancel them in mgd_stop logic that tears down
the station.
This fixes the crashes we see in 3.7.9+. The crash stack
trace itself isn't so helpful, but this warning gives
more useful info:
WARNING: at /home/greearb/git/linux-3.7.dev.y/lib/debugobjects.c:261 debug_print_object+0x7c/0x8d()
ODEBUG: free active (active state 0) object type: work_struct hint: ieee80211_sta_monitor_work+0x0/0x14 [mac80211]
Modules linked in: [...]
Pid: 14743, comm: iw Tainted: G C O 3.7.9+ #11
Call Trace:
[<ffffffff81087ef8>] warn_slowpath_common+0x80/0x98
[<ffffffff81087fa4>] warn_slowpath_fmt+0x41/0x43
[<ffffffff812a2608>] debug_print_object+0x7c/0x8d
[<ffffffff812a2bca>] debug_check_no_obj_freed+0x95/0x1c3
[<ffffffff8114cc69>] slab_free_hook+0x70/0x79
[<ffffffff8114ea3e>] kfree+0x62/0xb7
[<ffffffff8149f465>] netdev_release+0x39/0x3e
[<ffffffff8136ad67>] device_release+0x52/0x8a
[<ffffffff812937db>] kobject_release+0x121/0x158
[<ffffffff81293612>] kobject_put+0x4c/0x50
[<ffffffff8148f0d7>] netdev_run_todo+0x25c/0x27e
Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mac80211/mlme.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -4072,6 +4072,17 @@ void ieee80211_mgd_stop(struct ieee80211
{
struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+ /*
+ * Make sure some work items will not run after this,
+ * they will not do anything but might not have been
+ * cancelled when disconnecting.
+ */
+ cancel_work_sync(&ifmgd->monitor_work);
+ cancel_work_sync(&ifmgd->beacon_connection_loss_work);
+ cancel_work_sync(&ifmgd->request_smps_work);
+ cancel_work_sync(&ifmgd->csa_connection_drop_work);
+ cancel_work_sync(&ifmgd->chswitch_work);
+
mutex_lock(&ifmgd->mtx);
if (ifmgd->assoc_data)
ieee80211_destroy_assoc_data(sdata, false);
--
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