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

On Fri, May 28, 2021 at 06:44:37PM +0200, Ahmed S. Darwish wrote:

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@suse.com

Acked-by: Ahmed S. Darwish a.darwish@linutronix.de

Applied, thanks a lot!