Messages in this thread | | | From | Zhiguo Niu <> | Date | Wed, 3 Apr 2024 14:00:22 +0800 | Subject | Re: [PATCH V4] lockdep: fix deadlock issue between lockdep and rcu |
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On Tue, Apr 2, 2024 at 11:41 PM Carlos Llamas <cmllamas@google.com> wrote: > > On Tue, Feb 06, 2024 at 07:44:55PM +0800, Zhiguo Niu wrote: > > There is a deadlock scenario between lockdep and rcu when > > rcu nocb feature is enabled, just as following call stack: > > > > rcuop/x > > -000|queued_spin_lock_slowpath(lock = 0xFFFFFF817F2A8A80, val = ?) > > -001|queued_spin_lock(inline) // try to hold nocb_gp_lock > > -001|do_raw_spin_lock(lock = 0xFFFFFF817F2A8A80) > > -002|__raw_spin_lock_irqsave(inline) > > -002|_raw_spin_lock_irqsave(lock = 0xFFFFFF817F2A8A80) > > -003|wake_nocb_gp_defer(inline) > > -003|__call_rcu_nocb_wake(rdp = 0xFFFFFF817F30B680) > > -004|__call_rcu_common(inline) > > -004|call_rcu(head = 0xFFFFFFC082EECC28, func = ?) > > -005|call_rcu_zapped(inline) > > -005|free_zapped_rcu(ch = ?)// hold graph lock > > -006|rcu_do_batch(rdp = 0xFFFFFF817F245680) > > -007|nocb_cb_wait(inline) > > -007|rcu_nocb_cb_kthread(arg = 0xFFFFFF817F245680) > > -008|kthread(_create = 0xFFFFFF80803122C0) > > -009|ret_from_fork(asm) > > > > rcuop/y > > -000|queued_spin_lock_slowpath(lock = 0xFFFFFFC08291BBC8, val = 0) > > -001|queued_spin_lock() > > -001|lockdep_lock() > > -001|graph_lock() // try to hold graph lock > > -002|lookup_chain_cache_add() > > -002|validate_chain() > > -003|lock_acquire > > -004|_raw_spin_lock_irqsave(lock = 0xFFFFFF817F211D80) > > -005|lock_timer_base(inline) > > -006|mod_timer(inline) > > -006|wake_nocb_gp_defer(inline)// hold nocb_gp_lock > > -006|__call_rcu_nocb_wake(rdp = 0xFFFFFF817F2A8680) > > -007|__call_rcu_common(inline) > > -007|call_rcu(head = 0xFFFFFFC0822E0B58, func = ?) > > -008|call_rcu_hurry(inline) > > -008|rcu_sync_call(inline) > > -008|rcu_sync_func(rhp = 0xFFFFFFC0822E0B58) > > -009|rcu_do_batch(rdp = 0xFFFFFF817F266680) > > -010|nocb_cb_wait(inline) > > -010|rcu_nocb_cb_kthread(arg = 0xFFFFFF817F266680) > > -011|kthread(_create = 0xFFFFFF8080363740) > > -012|ret_from_fork(asm) > > > > rcuop/x and rcuop/y are rcu nocb threads with the same nocb gp thread. > > This patch release the graph lock before lockdep call_rcu. > > > > Fixes: a0b0fd53e1e6 ("locking/lockdep: Free lock classes that are no longer in use") > > Cc: <stable@vger.kernel.org> > > Cc: Boqun Feng <boqun.feng@gmail.com> > > Cc: Waiman Long <longman@redhat.com> > > Cc: Carlos Llamas <cmllamas@google.com> > > Cc: Bart Van Assche <bvanassche@acm.org> > > Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com> > > Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com> > > Reviewed-by: Boqun Feng <boqun.feng@gmail.com> > > Reviewed-by: Waiman Long <longman@redhat.com> > > Reviewed-by: Carlos Llamas <cmllamas@google.com> > > Reviewed-by: Bart Van Assche <bvanassche@acm.org> > > --- > > This patch should be good to go. Maybe it just slipped through the > cracks. Ingo, will you be taking this?
Hi Carlos, Thanks for restoring this mail and now this patch can only be temporarily included in my code locally when I do related jobs. and hope someone can help merge it if there are no review suggestions. > > -- > Carlos Llamas
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