[Linux-kernel-mentees] [PATCH] net: batman-adv: Use built-in RCU list checking

Sven Eckelmann sven at narfation.org
Sun Feb 16 15:35:54 UTC 2020


On Sunday, 16 February 2020 16:33:24 CET Madhuparna Bhowmik wrote:
[...]
> > Can you tell us how you've identified these four hlist_for_each_entry_rcu?
>
> The other hlist_for_each_entry_rcu() are used under the protection of
> rcu_read_lock(). We only need to pass the cond when
> hlist_for_each_entry_rcu() is used under a
> different lock (not under rcu_red_lock()) because according to the current scheme a lockdep splat
> is generated when hlist_for_each_entry_rcu() is used outside of
> rcu_read_lock() or the lockdep condition (the cond argument) evaluates
> to false. So, we need to pass this cond when it is used under the
> protection of spinlock or mutex etc. and not required if rcu_read_lock()
> is used.

I understand this part. I was asking how you've identified them. Did you use 
any tool for that? coccinelle, sparse, ...

Kind regards,
	Sven
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