From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luis Claudio R. Goncalves" Subject: [4.4.4-rt11] Possiblie recursive locking detected in kswapd / mb_cache_shrink_scan() Date: Mon, 14 Mar 2016 18:00:58 -0300 Message-ID: <20160314210058.GE29798@uudg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-rt-users@vger.kernel.org Return-path: Received: from mail-qg0-f43.google.com ([209.85.192.43]:36312 "EHLO mail-qg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933307AbcCNVBD (ORCPT ); Mon, 14 Mar 2016 17:01:03 -0400 Received: by mail-qg0-f43.google.com with SMTP id u110so165326799qge.3 for ; Mon, 14 Mar 2016 14:01:02 -0700 (PDT) Received: from lclaudio.dyndns.org (179.176.232.10.dynamic.adsl.gvt.net.br. [179.176.232.10]) by smtp.gmail.com with ESMTPSA id 139sm11112644qho.2.2016.03.14.14.01.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 14 Mar 2016 14:01:01 -0700 (PDT) Content-Disposition: inline Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hello, I just started using 4.4.4-rt11 this afternoon and saw the lockdep splat below. Is this something new or did I miss a patch floating on the list? [67547.917898] ============================================= [67547.917898] [ INFO: possible recursive locking detected ] [67547.917900] 4.4.4-rt11 #4 Not tainted [67547.917900] --------------------------------------------- [67547.917901] kswapd0/59 is trying to acquire lock: [67547.917908] (&h->lock#2){+.+.-.}, at: [] mb_cache_shrink_scan+0xac/0x220 [67547.917908] but task is already holding lock: [67547.917910] (&h->lock#2){+.+.-.}, at: [] mb_cache_shrink_scan+0x9a/0x220 [67547.917911] other info that might help us debug this: [67547.917911] Possible unsafe locking scenario: [67547.917911] CPU0 [67547.917911] ---- [67547.917912] lock(&h->lock#2); [67547.917913] lock(&h->lock#2); [67547.917913] *** DEADLOCK *** [67547.917913] May be due to missing lock nesting notation [67547.917914] 2 locks held by kswapd0/59: [67547.917917] #0: (shrinker_rwsem){+.+...}, at: [] rt_down_read_trylock+0x22/0x30 [67547.917919] #1: (&h->lock#2){+.+.-.}, at: [] mb_cache_shrink_scan+0x9a/0x220 [67547.917920] stack backtrace: [67547.917921] CPU: 0 PID: 59 Comm: kswapd0 Not tainted 4.4.4-rt11 #4 [67547.917922] Hardware name: Hewlett-Packard p7-1512/2ADA, BIOS 8.15 02/05/2013 [67547.917923] 0000000000000086 000000005fca2e71 ffff88018a9fba10 ffffffff813d5412 [67547.917925] ffffffff828ede50 ffff88018a9f4000 ffff88018a9fbb00 ffffffff810e0d66 [67547.917926] ffff88018a9fbb08 000000000000008a ffffffff828e58a0 ffffffff81c0bf18 [67547.917926] Call Trace: [67547.917929] [] dump_stack+0x67/0x95 [67547.917931] [] __lock_acquire+0x1cf6/0x1d30 [67547.917934] [] ? debug_smp_processor_id+0x17/0x20 [67547.917936] [] ? mark_held_locks+0x79/0xa0 [67547.917940] [] ? _raw_spin_unlock_irqrestore+0x6c/0x80 [67547.917941] [] lock_acquire+0xf7/0x240 [67547.917942] [] ? mb_cache_shrink_scan+0xac/0x220 [67547.917944] [] _raw_spin_lock+0x41/0x80 [67547.917945] [] ? mb_cache_shrink_scan+0xac/0x220 [67547.917946] [] mb_cache_shrink_scan+0xac/0x220 [67547.917949] [] shrink_slab.part.41+0x24a/0x600 [67547.917951] [] shrink_zone+0x2ca/0x2e0 [67547.917953] [] kswapd+0x581/0xbc0 [67547.917955] [] ? mem_cgroup_shrink_node_zone+0x3c0/0x3c0 [67547.917957] [] kthread+0x101/0x120 [67547.917959] [] ? kthread_create_on_node+0x250/0x250 [67547.917960] [] ret_from_fork+0x3f/0x70 [67547.917962] [] ? kthread_create_on_node+0x250/0x250 Best regards, Luis