Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757284Ab2JWQq3 (ORCPT ); Tue, 23 Oct 2012 12:46:29 -0400 Received: from fieldses.org ([174.143.236.118]:36819 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757110Ab2JWQq1 (ORCPT ); Tue, 23 Oct 2012 12:46:27 -0400 Date: Tue, 23 Oct 2012 12:46:21 -0400 From: "J. Bruce Fields" To: Nix Cc: "Ted Ts'o" , linux-kernel@vger.kernel.org, Bryan Schumaker , Peng Tao , Trond.Myklebust@netapp.com, gregkh@linuxfoundation.org, linux-nfs@vger.kernel.org, Stanislav Kinsbursky Subject: Re: Heads-up: 3.6.2 / 3.6.3 NFS server oops: 3.6.2+ regression? (also an unrelated ext4 data loss bug) Message-ID: <20121023164621.GC3040@fieldses.org> References: <87objupjlr.fsf@spindle.srvr.nix> <20121023013343.GB6370@fieldses.org> <87mwzdnuww.fsf@spindle.srvr.nix> <20121023143019.GA3040@fieldses.org> <874nllxi7e.fsf_-_@spindle.srvr.nix> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <874nllxi7e.fsf_-_@spindle.srvr.nix> 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: 7125 Lines: 132 On Tue, Oct 23, 2012 at 05:32:21PM +0100, Nix wrote: > On 23 Oct 2012, J. Bruce Fields uttered the following: > > nfs-utils shouldn't be capable of oopsing the kernel, so from my > > (selfish) point of view I'd actually rather you stick with whatever you > > have and try to reproduce the oops. > > Reproduced in 3.6.3, not in 3.6.1, not tried 3.6.2. Capturing it was > rendered somewhat difficult by an ext4/JBD2 bug which leads to data loss > in /var on every reboot out of 3.6.1 and on some reboots out of 3.6.3 (I > have runs of NULs in my logs now, which keep eating the oopses): > > [while in 3.6.1] > [ 88.565698] JBD2: Spotted dirty metadata buffer (dev = dm-5, blocknr = 0). There's a risk of filesystem corruption in case of system crash. > [ 88.799263] JBD2: Spotted dirty metadata buffer (dev = dm-5, blocknr = 0). There's a risk of filesystem corruption in case of system crash. > [ 89.648152] ------------[ cut here ]------------ > [ 89.648386] WARNING: at fs/inode.c:280 drop_nlink+0x25/0x42() > [ 89.648614] Hardware name: empty > [ 89.648833] Modules linked in: firewire_ohci firewire_core [last unloaded: microcode] > [ 89.649382] Pid: 1484, comm: dhcpd Not tainted 3.6.1-dirty #1 > [ 89.649610] Call Trace: > [ 89.649832] [] warn_slowpath_common+0x83/0x9b > [ 89.650063] [] warn_slowpath_null+0x1a/0x1c > [ 89.650292] [] drop_nlink+0x25/0x42 > [ 89.650533] [] ext4_dec_count+0x26/0x28 > [ 89.650763] [] ext4_rename+0x4ec/0x7b4 > [ 89.650993] [] ? vfs_rename+0xbe/0x3b7 > [ 89.651224] [] vfs_rename+0x27c/0x3b7 > [ 89.651454] [] sys_renameat+0x1b1/0x228 > [ 89.651682] [] ? fsnotify+0x226/0x249 > [ 89.651911] [] ? security_inode_permission+0x1e/0x20 > [ 89.652145] [] ? vfs_write+0x116/0x142 > [ 89.652372] [] sys_rename+0x1b/0x1e > [ 89.652601] [] system_call_fastpath+0x16/0x1b > [...] > [while having just booted into 3.6.1 after some time in 3.6.3: the FS > was clean, and fscked on the previous boot into 3.6.3 after a previous > instance of this bug] > Oct 23 17:18:26 spindle crit: [ 67.625319] EXT4-fs error (device dm-5): mb_free_blocks:1300: group 65, block 2143748:freeing already freed block (bit 13828) > > This may well be a 3.6.1-specific bug fixed in 3.6.3, but it's hard to > tell since most of my reboots are 3.6.1->3.6.3 or vice versa right now. > > > Anyway, here's the NFSv4 oops (not a panic: it helps if I remember to > turn off panic_on_oops when I come home from the holidays). > > It's a lockd problem, and probably happens during delivery of mail over > NFS (my mailserver load soars when it happens): > > [ 813.110354] ------------[ cut here ]------------ > [ 813.110585] kernel BUG at fs/lockd/mon.c:150! So nsm_mon_unmon() is being passed a NULL client. There are three container patches between 3.6.1 and 3.6.3: lockd: per-net NSM client creation and destruction helpers introduced lockd: use rpc client's cl_nodename for id encoding lockd: create and use per-net NSM RPC clients on MON/UNMON requests and that last does change nsm_monitor's call to nsm_mon_unmon, so that's almost certainly it.... Looks like there's some confusion about whether nsm_client_get() returns NULL or an error? --b. > [ 813.110878] invalid opcode: 0000 [#1] SMP > [ 813.111173] Modules linked in: firewire_ohci firewire_core [last unloaded: microcode] > [ 813.111727] CPU 1 > [ 813.111772] Pid: 1040, comm: lockd Not tainted 3.6.3-dirty #1 empty empty/S7010 > [ 813.112388] RIP: 0010:[] [] nsm_mon_unmon+0x64/0x98 > [ 813.112840] RSP: 0018:ffff88062163dcf0 EFLAGS: 00010246 > [ 813.113069] RAX: ffff88062163dcf8 RBX: 0000000000000000 RCX: 0000000000000000 > [ 813.113303] RDX: ffff88062163dd68 RSI: 0000000000000002 RDI: ffff88062163dd40 > [ 813.113537] RBP: ffff88062163dd50 R08: 0000000000000000 R09: ffffffff8120c463 > [ 813.113771] R10: ffffffff8120c463 R11: 0000000000000001 R12: 0000000000000000 > [ 813.114006] R13: ffff88061f067e40 R14: ffff88059c763a00 R15: ffff88062163de28 > [ 813.114241] FS: 0000000000000000(0000) GS:ffff88063fc40000(0000) knlGS:0000000000000000 > [ 813.114651] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 813.114882] CR2: ffffffffff600400 CR3: 0000000001a0b000 CR4: 00000000000007e0 > [ 813.115116] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 813.115350] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > [ 813.115584] Process lockd (pid: 1040, threadinfo ffff88062163c000, task ffff880621611640) > [ 813.115994] Stack: > [ 813.116210] ffff88062163dd90 ffff8805f4e044b1 00000003000186b5 ffffffff00000010 > [ 813.116761] ffff8805f4e044c1 000000000000008c 0000000000000000 ffff88062163dcf8 > [ 813.117310] ffff88062163dd68 0000000000000000 ffff8806200ce088 ffff8805f4e04400 > [ 813.117861] Call Trace: > [ 813.118083] [] nsm_monitor+0x100/0x157 > [ 813.118315] [] nlm4svc_retrieve_args+0x62/0xd7 > [ 813.118547] [] nlm4svc_proc_lock+0x3c/0xb5 > [ 813.118779] [] ? nlm4svc_decode_lockargs+0x47/0xb2 > [ 813.119016] [] svc_process+0x3bf/0x6a1 > [ 813.119246] [] lockd+0x127/0x164 > [ 813.119474] [] ? set_grace_period+0x8a/0x8a > [ 813.119708] [] kthread+0x8b/0x93 > [ 813.119938] [] kernel_thread_helper+0x4/0x10 > [ 813.120170] [] ? kthread_worker_fn+0xe1/0xe1 > [ 813.120401] [] ? gs_change+0xb/0xb > [ 813.120628] Code: b8 10 00 00 00 48 89 45 c0 48 8d 81 8c 00 00 00 b9 08 00 00 00 48 89 45 c8 89 d8 f3 ab 48 8d 45 a8 48 89 55 e0 48 89 45 d8 75 02 <0f> 0b 89 f6 48 c7 02 00 00 00 00 4c 89 c7 48 6b f6 38 ba 00 04 > [ 813.123627] RIP [] nsm_mon_unmon+0x64/0x98 > [ 813.123894] RSP > [ 813.124129] ---[ end trace 11eb11a091ffd910 ]--- > > Aside: I am running with this patch, to prevent mounting of one > NFS-mounted directory under another from failing all accesses with a > spurious -EBUSY, a 3.6 regression -- but I can't see how this could > cause it. I'm running with this in 3.6.1 as well: > > diff --git a/fs/dcache.c b/fs/dcache.c > index 8086636..649a112 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -2404,6 +2404,10 @@ out_unalias: > if (likely(!d_mountpoint(alias))) { > __d_move(alias, dentry); > ret = alias; > + } else { > + printk(KERN_WARNING "VFS: __d_move()ing a d_mountpoint(), uh oh\n"); > + __d_move(alias, dentry); > + ret = alias; > } > out_err: > spin_unlock(&inode->i_lock); > -- 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/