Messages in this thread | | | Date | Tue, 2 Apr 2024 15:41:02 +0000 | From | Carlos Llamas <> | Subject | Re: [PATCH V4] lockdep: fix deadlock issue between lockdep and rcu |
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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?
-- Carlos Llamas
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