Re: [PATCH net-next 1/2] ieee802154: sparse warnings: make symbols static

Hi Eric,

just a several questions:

quoted

quoted

static DEFINE_SPINLOCK(flist_lock);

and of course commit 768f7c7c121e80f4 (6lowpan: add missing
spin_lock_init() ) must be reverted.

Do I need to create 2 separate patches: one for revert and second to
initialize spinlock correctly, or I can combine these changes in one
patch?

You should validate this code with LOCKDEP

Nothing was shown by LOCKDEP for 6lowpan. :-(

I've selected the following options:

-*- Spinlock and rw-lock debugging: basic checks
-*- Mutex debugging: basic checks
-*- Lock debugging: detect incorrect freeing of live locks
[*] Lock usage statistics
[*] Lock dependency engine debugging

lowpan_dellink() does a spin_lock(&flist_lock);
while same lock can be taken by lowpan_fragment_timer_expired() from
timer irq, -> deadlock.

What would be the best way to solve this context mismatch? Can I do
something like following:
1. create some 6lowpan internal workqueue
2. replace lowpan_fragment_timer_expired() body by queue_work() with
current list_deleting routine
3. when 6lowpan is going to be deleted - I'll flush the queue and
remove all the timers and respective fragments

Alex