Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757413Ab2JWTur (ORCPT ); Tue, 23 Oct 2012 15:50:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33601 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756875Ab2JWTup (ORCPT ); Tue, 23 Oct 2012 15:50:45 -0400 Date: Tue, 23 Oct 2012 15:50:26 -0400 From: Dave Jones To: Peter Zijlstra Cc: Linux Kernel , Ingo Molnar Subject: Re: MAX_LOCKDEP_ENTRIES too low Message-ID: <20121023195026.GA2872@redhat.com> Mail-Followup-To: Dave Jones , Peter Zijlstra , Linux Kernel , Ingo Molnar References: <20121018015312.GA29865@redhat.com> <507F9944.50505@kernel.dk> <20121019052136.GA30852@redhat.com> <1350650972.30157.34.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1350650972.30157.34.camel@twins> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3876 Lines: 69 On Fri, Oct 19, 2012 at 02:49:32PM +0200, Peter Zijlstra wrote: > > Not sure why this suddenly got a lot worse in 3.7 > > Did we add a static array of structures with locks in somewhere? Doing > that is a great way of blowing up the number of lock classes and the > resulting amount of lock dependency chains. So I hit it again, but didn't see anything that I hadn't seen already in /proc/lockdep. I so tried doubling MAX_LOCKDEP_ENTRIES again. A while later, I got this oops. I'm unsure now if this is a genuine bug, or a side-effect of lockdep not working with such a large MAX_LOCKDEP_ENTRIES opinions ? BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [] __lock_acquire+0x5e/0x1ba0 PGD 8e72c067 PUD 34f07067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: fuse nfnetlink ipt_ULOG binfmt_misc nfc caif_socket caif phonet can llc2 pppoe pppox ppp_generic slhc irda crc_ccitt rds af_key decnet rose x25 atm netrom appletalk ipx p8023 psnap p8022 llc ax25 lockd sunrpc bluetooth rfkill ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables kvm_intel kvm usb_debug crc32c_intel ghash_clmulni_intel microcode pcspkr i2c_i801 e1000e uinput i915 video i2c_algo_bit drm_kms_helper drm i2c_core CPU 7 Pid: 27513, comm: trinity-child0 Not tainted 3.7.0-rc2+ #43 Intel Corporation 2012 Client Platform/Emerald Lake 2 RIP: 0010:[] [] __lock_acquire+0x5e/0x1ba0 RSP: 0018:ffff8800803f7b28 EFLAGS: 00010046 RAX: 0000000000000086 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000018 RBP: ffff8800803f7c18 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000000000 R11: 2222222222222222 R12: 0000000000000002 R13: ffff880051dd8000 R14: 0000000000000002 R15: 0000000000000018 FS: 00007f9fc6ccb740(0000) GS:ffff880148a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000008e6fb000 CR4: 00000000001407e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process trinity-child0 (pid: 27513, threadinfo ffff8800803f6000, task ffff880051dd8000) Stack: ffff8800803f7b48 ffffffff816c5c59 ffff8800803f7b48 ffff88014840ebc0 ffff8800803f7b68 ffffffff816c18e3 ffff8800803f7d10 0000000000000001 ffff8800803f7ba8 ffffffff810a1e62 ffff8800803f7d10 0000000000000282 Call Trace: [] ? sub_preempt_count+0x79/0xd0 [] ? _raw_spin_unlock_irqrestore+0x73/0xa0 [] ? hrtimer_try_to_cancel+0x52/0x210 [] ? debug_rt_mutex_free_waiter+0x15/0x180 [] ? rt_mutex_slowlock+0x127/0x1b0 [] ? local_clock+0x89/0xa0 [] lock_acquire+0xa2/0x220 [] ? futex_lock_pi.isra.18+0x1cc/0x390 [] _raw_spin_lock+0x40/0x80 [] ? futex_lock_pi.isra.18+0x1cc/0x390 [] futex_lock_pi.isra.18+0x1cc/0x390 [] ? update_rmtp+0x70/0x70 [] do_futex+0x394/0xa50 [] ? might_fault+0x53/0xb0 [] sys_futex+0x8d/0x190 [] tracesys+0xe1/0xe6 Code: d8 45 0f 45 e0 4c 89 75 f0 4c 89 7d f8 85 c0 0f 84 f8 00 00 00 8b 05 22 fe f3 00 49 89 ff 89 f3 41 89 d2 85 c0 0f 84 02 01 00 00 <49> 8b 07 ba 01 00 00 00 48 3d c0 81 06 82 44 0f 44 e2 83 fb 01 RIP [] __lock_acquire+0x5e/0x1ba0 RSP CR2: 0000000000000018 -- 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/