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[185.121.47.193]) by smtp.gmail.com with ESMTPSA id d8-20020ac241c8000000b00515fc468f45sm390542lfi.31.2024.03.31.00.25.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 Mar 2024 00:25:58 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Sun, 31 Mar 2024 09:25:56 +0200 To: Hillf Danton Cc: Uladzislau Rezki , syzbot , Alexei Starovoitov , "Paul E. McKenney" , linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [bpf?] possible deadlock in kvfree_call_rcu Message-ID: References: <000000000000f2f0c0061494e610@google.com> <20240331062314.3394-1-hdanton@sina.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240331062314.3394-1-hdanton@sina.com> On Sun, Mar 31, 2024 at 02:23:14PM +0800, Hillf Danton wrote: > On Sat, 30 Mar 2024 18:55:41 +0100 Uladzislau Rezki > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index d9642dd06c25..8867aac3668c 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -3467,19 +3467,19 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr) > > */ > > kmemleak_ignore(ptr); > > > > - // Set timer to drain after KFREE_DRAIN_JIFFIES. > > - if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING) > > - schedule_delayed_monitor_work(krcp); > > - > > This is not enough at least WRT run_page_cache_worker() [1] > > [1] https://lore.kernel.org/lkml/0000000000007a44120614e27cb7@google.com/ > page-cache-worker should be move out of the krcp-lock also. I will update the patch. -- Uladzislau Rezki