Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752940Ab3CHTg5 (ORCPT ); Fri, 8 Mar 2013 14:36:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:17323 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750917Ab3CHTg4 (ORCPT ); Fri, 8 Mar 2013 14:36:56 -0500 Date: Fri, 8 Mar 2013 14:36:52 -0500 From: Dave Jones To: Linus Torvalds , Linux Kernel , Al Viro Subject: Re: BUG_ON(nd->inode != parent->d_inode); Message-ID: <20130308193652.GA11692@redhat.com> Mail-Followup-To: Dave Jones , Linus Torvalds , Linux Kernel , Al Viro References: <20130307021645.GA10173@redhat.com> <20130308150408.GA25399@redhat.com> <20130308191804.GA9774@redhat.com> <20130308192042.GA10305@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130308192042.GA10305@redhat.com> 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: 4773 Lines: 90 On Fri, Mar 08, 2013 at 02:20:42PM -0500, Dave Jones wrote: > > I'll turn off DEBUG_PAGEALLOC again, so I can get the RIP and figure out which deref it is. > > Wait, it has to be that path->dentry->d_name.name. > The other derefs are the same as before. I changed it to do this.. diff --git a/fs/namei.c b/fs/namei.c index 961bc12..c1ca29e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -689,8 +689,6 @@ void nd_jump_link(struct nameidata *nd, struct path *path) nd->path = *path; nd->inode = nd->path.dentry->d_inode; nd->flags |= LOOKUP_JUMPED; - - BUG_ON(nd->inode->i_op->follow_link); } static inline void put_link(struct nameidata *nd, struct path *link, void *cookie) @@ -1438,7 +1436,13 @@ static int lookup_slow(struct nameidata *nd, struct path *path) int err; parent = nd->path.dentry; - BUG_ON(nd->inode != parent->d_inode); + + if (WARN_ON(nd->inode != parent->d_inode)) { + printk("%s -> %p (%s)\n", parent->d_name.name, path->dentry, nd->last.name); + return -EINVAL; + } + + mutex_lock(&parent->d_inode->i_mutex); dentry = __lookup_hash(&nd->last, parent, nd->flags); And now I'm getting a different BUG_ON [ 170.860317] kernel BUG at fs/namei.c:2737! [ 170.860855] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 170.861719] Modules linked in: irda can phonet ipx p8023 p8022 af_rxrpc atm x25 af_802154 llc2 pppoe pppox ppp_generic slhc netrom decnet af_key rose nfc ax25 appletalk psnap llc caif_socket caif crc_ccitt rds lockd sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack nf_conntrack ip6table_filter ip6_tables btusb bluetooth snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_pcm snd_page_alloc microcode usb_debug snd_timer vhost_net snd rfkill serio_raw tun edac_core pcspkr macvtap soundcore macvlan kvm_amd r8169 mii kvm radeon backlight drm_kms_helper ttm [ 170.869795] CPU 1 [ 170.870063] Pid: 998, comm: trinity-child1 Not tainted 3.9.0-rc1+ #80 Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H [ 170.871541] RIP: 0010:[] [] do_last+0xda4/0xe30 [ 170.872561] RSP: 0018:ffff880108577cc8 EFLAGS: 00010206 [ 170.873250] RAX: 0000000000000001 RBX: ffff880108577e58 RCX: 0000000000000000 [ 170.874162] RDX: 000000000000006d RSI: ffff880108819660 RDI: 0000000000000001 [ 170.875073] RBP: ffff880108577d98 R08: 0000000000000001 R09: 0000000000000000 [ 170.875986] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000008000 [ 170.876898] R13: ffff880108577df8 R14: ffff880108577f28 R15: ffff88010875c840 [ 170.877810] FS: 00007f5651395740(0000) GS:ffff88012a800000(0000) knlGS:0000000000000000 [ 170.878838] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 170.879580] CR2: 0000000000fe1418 CR3: 0000000108655000 CR4: 00000000000007e0 [ 170.880491] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 170.881402] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 170.882314] Process trinity-child1 (pid: 998, threadinfo ffff880108576000, task ffff880108578000) [ 170.883436] Stack: [ 170.883696] ffff8801159b5e48 ffff880108578000 ffff880108577ce8 ffffffff811c8088 [ 170.884746] ffff880108577d98 ffffffff811c8305 ffff880122444620 ffff880122444600 [ 170.885806] ffff880108577d28 ffff880108578000 ffff880108578000 ffff880108577d58 [ 170.886840] Call Trace: [ 170.887181] [] ? inode_permission+0x18/0x50 [ 170.887939] [] ? link_path_walk+0x245/0x880 [ 170.888697] [] path_openat+0xba/0x500 [ 170.889392] [] ? trace_hardirqs_off_caller+0x28/0xc0 [ 170.890245] [] ? get_lock_stats+0x22/0x70 [ 170.890980] [] ? put_lock_stats.isra.23+0xe/0x40 [ 170.891790] [] do_filp_open+0x41/0xa0 [ 170.892485] [] ? __alloc_fd+0x179/0x230 [ 170.893200] [] do_sys_open+0xf4/0x1e0 [ 170.893893] [] sys_openat+0x14/0x20 [ 170.894565] [] system_call_fastpath+0x16/0x1b [ 170.895342] Code: 66 f8 ff ff 41 ba e6 ff ff ff e9 b2 f8 ff ff 0f 8c eb f4 ff ff 48 8b 75 90 c6 45 ac 00 48 8b 76 30 48 39 73 30 0f 84 8a f5 ff ff <0f> 0b be e9 09 00 00 48 c7 c7 37 8c a0 81 4c 89 9d 48 ff ff ff BUG_ON(nd->inode != dir->d_inode); It also looks like that printk didn't fire. Hmm.. Different bug ? Christ, I'm having a hard time keeping track of all these. Dave -- 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/