From: Boqun Feng <boqun.feng@gmail.com>
To: Hillf Danton <hdanton@sina.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 09:58:10 -0800 [thread overview]
Message-ID: <Y8GbsulOXWNK9WGs@boqun-archlinux> (raw)
In-Reply-To: <20230113130330.1027-1-hdanton@sina.com>
On Fri, Jan 13, 2023 at 09:03:30PM +0800, Hillf Danton wrote:
> 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
But isn't it just the srcu_mutex_ABBA test case in patch #3, and my run
of lockdep selftest shows we can catch it. Anything subtle I'm missing?
Regards,
Boqun
next prev parent reply other threads:[~2023-01-13 17:58 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 6:59 [PATCH 0/3] Detect SRCU related deadlocks Boqun Feng
2023-01-13 6:59 ` [PATCH 1/3] locking/lockdep: Introduce lock_sync() Boqun Feng
2023-01-16 21:56 ` Waiman Long
2023-01-13 6:59 ` [PATCH 2/3] rcu: Equip sleepable RCU with lockdep dependency graph checks Boqun Feng
2023-01-13 11:29 ` Paul E. McKenney
2023-01-13 18:05 ` Boqun Feng
2023-01-13 19:11 ` Paul E. McKenney
2023-01-16 17:36 ` Paolo Bonzini
2023-01-16 17:54 ` Boqun Feng
2023-01-16 18:56 ` Paul E. McKenney
2023-01-13 13:03 ` Hillf Danton
2023-01-13 17:58 ` Boqun Feng [this message]
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
2023-01-16 22:01 ` Waiman Long
2023-01-13 6:59 ` [PATCH 3/3] WIP: locking/lockdep: selftests: Add selftests for SRCU Boqun Feng
2023-01-13 12:46 ` [PATCH 0/3] KVM: Make use of SRCU deadlock detection support David Woodhouse
2023-01-13 12:46 ` [PATCH 1/3] KVM: Show lockdep the kvm->mutex vs. kvm->srcu ordering rule David Woodhouse
2023-01-13 12:46 ` [PATCH 2/3] KVM: selftests: Use enum for test numbers in xen_shinfo_test David Woodhouse
2023-01-13 17:13 ` David Woodhouse
2023-01-13 12:46 ` [PATCH 3/3] KVM: selftests: Add EVTCHNOP_send slow path test to xen_shinfo_test David Woodhouse
2023-02-04 2:32 ` Sean Christopherson
2023-02-04 2:34 ` [PATCH 0/3] KVM: Make use of SRCU deadlock detection support Sean Christopherson
2023-01-13 23:57 ` [PATCH 4/3] locking/lockdep: Improve the deadlock scenario print for sync and read lock Boqun Feng
2023-01-16 22:21 ` Waiman Long
2023-01-16 22:35 ` Boqun Feng
2023-01-17 1:36 ` Waiman Long
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