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Brian Norris authored
If we fail to add an interface in mwifiex_add_virtual_intf(), we might hit a BUG_ON() in the networking code, because we didn't tear things down properly. Among the problems: (a) when failing to allocate workqueues, we fail to unregister the netdev before calling free_netdev() (b) even if we do try to unregister the netdev, we're still holding the rtnl lock, so the device never properly unregistered; we'll be at state NETREG_UNREGISTERING, and then hit free_netdev()'s: BUG_ON(dev->reg_state != NETREG_UNREGISTERED); (c) we're allocating some dependent resources (e.g., DFS workqueues) after we've registered the interface; this may or may not cause problems, but it's good practice to allocate these before registering (d) we're not even trying to unwind anything when mwifiex_send_cmd() or mwifiex_sta_init_cmd() fail To fix these issues, let's: * add a stacked set of error handling labels, to keep error handling consistent and properly ordered (resolving (a) and (d)) * move the workqueue allocations before the registration (to resolve (c); also resolves (b) by avoiding error cases where we have to unregister) [Incidentally, it's pretty easy to interrupt the alloc_workqueue() in, e.g., the following: iw phy phy0 interface add mlan0 type station by sending it SIGTERM.] This bugfix covers commits like commit 7d652034 ("mwifiex: channel switch support for mwifiex"), but parts of this bug exist all the way back to the introduction of dynamic interface handling in commit 93a1df48 ("mwifiex: add cfg80211 handlers add/del_virtual_intf"). Cc: <stable@vger.kernel.org> Signed-off-by:
Brian Norris <briannorris@chromium.org> Signed-off-by:
Kalle Valo <kvalo@codeaurora.org>
8535107a