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
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