This time, only RTNL locking reduction fallout.
- cfg80211_dev_rename() requires RTNL
- cfg80211_change_iface() and cfg80211_set_encryption()
require wiphy mutex (was missing in wireless extensions)
- cfg80211_destroy_ifaces() requires wiphy mutex
- netdev registration can fail due to notifiers, and then
notifiers are "unrolled", need to handle this properly
cfg80211: fix netdev registration deadlock
If register_netdevice() fails after having called cfg80211's
netdev notifier (cfg80211_netdev_notifier_call) it will call
the notifier again with UNREGISTER. This would then lock the
wiphy mutex because we're marked as registered, which causes
a deadlock.
Fix this by separately keeping track of whether or not we're
in the middle of registering to also skip the notifier call
on this unregister.
Reported-by: syzbot+2ae0ca9d7737ad1a62b7@syzkaller.appspotmail.com
Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver")
Link: https://lore.kernel.org/r/20210201192048.ed8bad436737.I7cae042c44b15f80919a285799a15df467e9d42d@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2 files changed
