From: Hillf Danton <hdanton@sina.com>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH 2/3] rcu: Equip sleepable RCU with lockdep dependency graph checks
Date: Fri, 13 Jan 2023 21:03:30 +0800 [thread overview]
Message-ID: <20230113130330.1027-1-hdanton@sina.com> (raw)
In-Reply-To: <20230113065955.815667-3-boqun.feng@gmail.com>
On 12 Jan 2023 22:59:54 -0800 Boqun Feng <boqun.feng@gmail.com>
> --- a/kernel/rcu/srcutree.c
> +++ b/kernel/rcu/srcutree.c
> @@ -1267,6 +1267,8 @@ static void __synchronize_srcu(struct srcu_struct *ssp, bool do_norm)
> {
> struct rcu_synchronize rcu;
>
> + srcu_lock_sync(&ssp->dep_map);
> +
> RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
> lock_is_held(&rcu_bh_lock_map) ||
> lock_is_held(&rcu_lock_map) ||
> --
> 2.38.1
The following deadlock is able to escape srcu_lock_sync() because the
__lock_release folded in sync leaves one lock on the sync side.
cpu9 cpu0
--- ---
lock A srcu_lock_acquire(&ssp->dep_map);
srcu_lock_sync(&ssp->dep_map);
lock A
next parent reply other threads:[~2023-01-13 13:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230113065955.815667-1-boqun.feng@gmail.com>
[not found] ` <20230113065955.815667-3-boqun.feng@gmail.com>
2023-01-13 13:03 ` Hillf Danton [this message]
2023-01-13 17:58 ` Boqun Feng
2023-01-13 23:58 ` Hillf Danton
2023-01-14 0:17 ` Boqun Feng
2023-01-14 7:18 ` Hillf Danton
2023-01-14 7:32 ` Boqun Feng
2023-01-14 10:26 ` Hillf Danton
2023-01-15 0:18 ` Boqun Feng
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