On Tuesday, June 16, 2015 22:12:00 Marek Lindner wrote:
On Tuesday, June 16, 2015 15:17:23 Linus Lüssing wrote:
/* flag checks above + mcast_handler_lock prevents this */if (unlikely(!hlist_unhashed(node)))BUG();I don't think this will work because hlist_unhashed() checks for node->pprev being NULL or not. hlist_del_rcu() sets node->pprev to LIST_POISON2.
We could also use BUG_ON() for readability. Something like:
BUG_ON(node->pprev == LIST_POISON2);
Though there are not many code sections working with LIST_POISON2 outside the list handling code.
Correction: Sven pointed out that we should not depend on LIST_POISON2 as it may point to some valid code or something utterly random depending on kernel configs.
I had overlooked that you had switched to hlist_del_init_rcu() already which makes your check valid. Still, would you consider using BUG_ON() ?
Cheers, Marek