Re: [PATCH v2] xfrm: policy: Read seqcount outside of rcu-read side in xfrm_policy_lookup_bytype

[Ahmed S. Darwish]

On Fri, May 28, 2021, Varad Gautam wrote:
>
> Thead 1 (xfrm_hash_resize)	Thread 2 (xfrm_policy_lookup_bytype)
>
> 				rcu_read_lock();
> mutex_lock(&hash_resize_mutex);
> 				read_seqcount_begin(&xfrm_policy_hash_generation);
> 				mutex_lock(&hash_resize_mutex); // block
> xfrm_bydst_resize();
> synchronize_rcu(); // block
> 		<RCU stalls in xfrm_policy_lookup_bytype>
>
...
>
> Fixes: 77cc278f7b20 ("xfrm: policy: Use sequence counters with associated lock")
> Signed-off-by: Varad Gautam <varad.gautam@xxxxxxxx>

Acked-by: Ahmed S. Darwish <a.darwish@xxxxxxxxxxxxx>