From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
To: Varad Gautam <varad.gautam@suse.com>
Cc: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>,
netdev@vger.kernel.org, stable@vger.kernel.org,
Steffen Klassert <steffen.klassert@secunet.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Florian Westphal <fw@strlen.de>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: Re: [PATCH v2] xfrm: policy: Read seqcount outside of rcu-read side in xfrm_policy_lookup_bytype
Date: Fri, 28 May 2021 18:44:37 +0200 [thread overview]
Message-ID: <YLEd9RS8Cebjv2ho@lx-t490> (raw)
In-Reply-To: <20210528160407.32127-1-varad.gautam@suse.com>
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>
next prev parent reply other threads:[~2021-05-28 16:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-28 12:03 [PATCH] xfrm: policy: Read seqcount outside of rcu-read side in xfrm_policy_lookup_bytype Varad Gautam
2021-05-28 15:11 ` Ahmed S. Darwish
2021-05-28 16:06 ` Varad Gautam
2021-05-28 16:04 ` [PATCH v2] " Varad Gautam
2021-05-28 16:44 ` Ahmed S. Darwish [this message]
2021-06-03 8:16 ` Steffen Klassert
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