Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751360AbbDBELy (ORCPT ); Thu, 2 Apr 2015 00:11:54 -0400 Received: from mga01.intel.com ([192.55.52.88]:63988 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750702AbbDBELx (ORCPT ); Thu, 2 Apr 2015 00:11:53 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,508,1422950400"; d="scan'208";a="701995921" Date: Thu, 2 Apr 2015 12:11:35 +0800 From: Fengguang Wu To: Herbert Xu Cc: LKP , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [rhashtable] [ INFO: suspicious RCU usage. ] Message-ID: <20150402041135.GA22514@wfg-t540p.sh.intel.com> References: <20150402005211.GC12979@wfg-t540p.sh.intel.com> <20150402035810.GA5408@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150402035810.GA5408@gondor.apana.org.au> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5846 Lines: 117 On Thu, Apr 02, 2015 at 11:58:10AM +0800, Herbert Xu wrote: > On Thu, Apr 02, 2015 at 08:52:11AM +0800, Fengguang Wu wrote: > > Hi Herbert, > > > > 0day kernel testing robot got the below dmesg and the first bad commit is > > > > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > > > commit ccd57b1bd32460d27bbb9c599e795628a3c66983 > > Author: Herbert Xu > > AuthorDate: Tue Mar 24 00:50:28 2015 +1100 > > Commit: David S. Miller > > CommitDate: Mon Mar 23 22:07:52 2015 -0400 > > > > rhashtable: Add immediate rehash during insertion > > > > This patch reintroduces immediate rehash during insertion. If > > we find during insertion that the table is full or the chain > > length exceeds a set limit (currently 16 but may be disabled > > with insecure_elasticity) then we will force an immediate rehash. > > The rehash will contain an expansion if the table utilisation > > exceeds 75%. > > > > If this rehash fails then the insertion will fail. Otherwise the > > insertion will be reattempted in the new hash table. > > > > Signed-off-by: Herbert Xu > > Acked-by: Thomas Graf > > Signed-off-by: David S. Miller > > > > [ 0.552992] Adding 2048 keys > > [ 0.553792] > > [ 0.554400] =============================== > > [ 0.555285] [ INFO: suspicious RCU usage. ] > > [ 0.556176] 4.0.0-rc4-01225-gccd57b1 #171 Not tainted > > [ 0.557156] ------------------------------- > > [ 0.558044] lib/rhashtable.c:400 suspicious rcu_dereference_check() usage! > > This should have been fixed by > > 58be8a583d8d316448bafa5926414cfb83c02dec. > > Can you check whether this commit was in your tested tree? Yes it is contained in next-20150401 which is bad: # extra tests on tree/branch next/master git bisect bad e954104e2b634b42811dad8d502cbf240f206df2 # 21:22 0- 60 Add linux-next specific files for 20150401 The dmesg there is [ 1.149409] test_firmware: interface ready [ 1.150293] Running resizable hashtable tests... [ 1.151209] Adding 2048 keys [ 1.152069] ------------[ cut here ]------------ [ 1.152978] WARNING: CPU: 0 PID: 1 at lib/rhashtable.c:409 rhashtable_insert_rehash+0x9d/0x1d0() [ 1.154802] Modules linked in: [ 1.155628] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc6-next-20150401 #1 [ 1.157185] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 1.159019] ffffffff81d1ce18 ffff880010dc3d18 ffffffff8189b1c3 0000000000000000 [ 1.160865] 0000000000000000 ffff880010dc3d58 ffffffff810b12aa ffff880010dc3d38 [ 1.162716] ffffffff8323a500 0000000000000010 ffff88000beda780 0000000000000001 [ 1.164558] Call Trace: [ 1.165249] [] dump_stack+0x4c/0x65 [ 1.166220] [] warn_slowpath_common+0x8a/0xc0 [ 1.167267] [] warn_slowpath_null+0x1a/0x20 [ 1.168317] [] rhashtable_insert_rehash+0x9d/0x1d0 [ 1.169415] [] test_rht_init+0x310/0x12ba [ 1.170425] [] ? do_one_initcall+0x80/0x200 [ 1.171466] [] ? test_firmware_init+0x79/0x79 [ 1.172524] [] do_one_initcall+0x90/0x200 [ 1.173552] [] kernel_init_freeable+0x22d/0x2b5 [ 1.174625] [] ? rest_init+0x140/0x140 [ 1.175617] [] kernel_init+0xe/0xf0 [ 1.176572] [] ret_from_fork+0x53/0x90 [ 1.177576] [] ? rest_init+0x140/0x140 [ 1.178570] ---[ end trace 0ba1594e5c63400d ]--- [ 1.179477] [ 1.180071] =============================== [ 1.180911] [ INFO: suspicious RCU usage. ] [ 1.181768] 4.0.0-rc6-next-20150401 #1 Tainted: G W [ 1.182818] ------------------------------- [ 1.183688] lib/test_rhashtable.c:176 suspicious rcu_dereference_check() usage! [ 1.185387] [ 1.185387] other info that might help us debug this: [ 1.185387] [ 1.187369] [ 1.187369] rcu_scheduler_active = 1, debug_locks = 0 [ 1.188835] no locks held by swapper/0/1. [ 1.189676] [ 1.189676] stack backtrace: [ 1.190917] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.0.0-rc6-next-20150401 #1 [ 1.192595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 1.194428] 0000000000000001 ffff880010dc3d78 ffffffff8189b1c3 0000000000000011 [ 1.196272] ffff880010db8000 ffff880010dc3da8 ffffffff81102d17 ffff880010f93d20 [ 1.207362] ffff88000c6530f0 0000000000000004 ffff88000beda6c0 ffff880010dc3e18 [ 1.209218] Call Trace: [ 1.209897] [] dump_stack+0x4c/0x65 [ 1.210867] [] lockdep_rcu_suspicious+0xe7/0x120 [ 1.211948] [] test_rht_init+0x1168/0x12ba [ 1.212968] [] ? do_one_initcall+0x80/0x200 [ 1.214007] [] ? test_firmware_init+0x79/0x79 [ 1.215060] [] do_one_initcall+0x90/0x200 [ 1.216075] [] kernel_init_freeable+0x22d/0x2b5 [ 1.217140] [] ? rest_init+0x140/0x140 [ 1.218130] [] kernel_init+0xe/0xf0 [ 1.219094] [] ret_from_fork+0x53/0x90 [ 1.220066] [] ? rest_init+0x140/0x140 [ 1.221075] glob: 64 self-tests passed, 0 failed Thanks, Fengguang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/