On Wed, 16 Sep 2015, Brian Foster wrote: > Date: Wed, 16 Sep 2015 06:50:23 -0400 > From: Brian Foster <bfoster@xxxxxxxxxx> > To: Grant Keller <grant.keller@xxxxxxxxx> > Cc: lczerner@xxxxxxxxxx, xfs@xxxxxxxxxxx > Subject: Re: rm Tainted warning after kernel update. > > cc Lukas > > On Tue, Sep 15, 2015 at 03:32:22PM -0700, Grant Keller wrote: > > On 09/15/2015 04:00 AM, Brian Foster wrote: > > > On Mon, Sep 14, 2015 at 11:57:37AM -0700, Grant Keller wrote: > > >> Hello, > > >> > > >> I have a server running Scientific Linux 6.7, and since updating to > > >> kernel 2.6.32-573.3.1.el6.x86_64 the following error has begun appearing > > >> in our message logs: > > >> > > >> Sep 14 11:43:03 localhost kernel: ------------[ cut here ]------------ > > >> Sep 14 11:43:03 localhost kernel: WARNING: at fs/dcache.c:758 > > >> d_delete+0x260/0x2c0() (Tainted: G W -- ------------ ) > > >> Sep 14 11:43:03 localhost kernel: Hardware name: X7DB8 > > >> Sep 14 11:43:03 localhost kernel: Modules linked in: nfsd nfs_acl > > >> auth_rpcgss autofs4 lockd sunrpc p4_clockmod freq_table speedstep_lib > > >> nf_conntrack_ftp iptable_mangle xt_comment nf_conntrack_ipv4 > > >> nf_defrag_ipv4 xt_multiport iptable_filter ip_tables ip6t_REJECT > > >> nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter > > >> ip6_tables ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm > > >> iw_cm ib_sa ib_mad ib_core ib_addr ipv6 xfs exportfs ppdev parport_pc > > >> parport sg e1000e microcode serio_raw iTCO_wdt iTCO_vendor_support ixgbe > > >> ptp pps_core mdio i2c_i801 lpc_ich mfd_core i5000_edac edac_core i5k_amb > > >> ioatdma dca shpchp ext4 jbd2 mbcache sd_mod crc_t10dif 3w_9xxx pata_acpi > > >> ata_generic ata_piix radeon ttm drm_kms_helper drm i2c_algo_bit i2c_core > > >> dm_mirror dm_region_hash dm_log dm_mod [last unloaded: ipmi_msghandler] > > >> Sep 14 11:43:03 localhost kernel: Pid: 15893, comm: rm Tainted: G > > >> W -- ------------ 2.6.32-573.3.1.el6.x86_64 #1 > > >> Sep 14 11:43:03 localhost kernel: Call Trace: > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff81077491>] ? > > >> warn_slowpath_common+0x91/0xe0 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff810774fa>] ? > > >> warn_slowpath_null+0x1a/0x20 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff811ae660>] ? > > >> d_delete+0x260/0x2c0 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff811a0908>] ? vfs_rmdir+0xe8/0xf0 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff811a3b64>] ? > > >> do_rmdir+0x184/0x1f0 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff81193511>] ? __fput+0x1a1/0x210 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff810e8ab7>] ? > > >> audit_syscall_entry+0x1d7/0x200 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff811a3bfd>] ? > > >> sys_unlinkat+0x2d/0x40 > > >> Sep 14 11:43:03 localhost kernel: [<ffffffff8100b0d2>] ? > > >> system_call_fastpath+0x16/0x1b > > >> Sep 14 11:43:03 localhost kernel: ---[ end trace 6080ec4a7ec5ec25 ]--- > > >> > > >> This happens when we are expiring older backups from the archives, so I > > >> have quite a few of these. We have xfsprogs 3.1.1-16.el6.x86_64 > > >> installed. Looking for advice on how to proceed. > > >> > > > This looks like something funky going on in the vfs. The warning is from > > > unhash_offsprings() and it appears to be complaining about a refcount on > > > a dentry that is a child of a directory being removed. It checks a > > > refcount on a dentry in one loop and either drops it or moves it to > > > another list for apparent deletion. The second iteration of the > > > aforementioned list sees a refcount on an object that wasn't there > > > before. > > > > > > I suspect this means something is going from 0->1 unexpectedly, but I'm > > > not familiar enough with that code to grok why that shouldn't happen and > > > how it could without reproducing it and digging into it from there. Have > > > you identified an explicit reproducer? I assume files are simply being > > > removed with 'rm -rf' here..? If so, does anything else have access to > > > this directory structure (e.g., separate commands, a running backup > > > application?) at the the time of removal. > > There could be something else running, but I would have to investigate > > the next time this happens. The rm -rf is called by our backup program > > expiring older backups from the filesystem. The thing is, the > > expirations happen on a nightly basis, but we don't always see these > > warnings in the logs. On the nights we do, there are 1000+ warnings. > > > > > > Also, what kernel were you running before this started to occur? > > 2.6.32-573.el6.x86_64 was the previous kernel. > > Interesting... there are only a few fs changes between this kernel and > the current. One of them is this: > > 959c503 [fs] vfs: Unhash and evict unused children dentries after rmdir > > ... which actually introduces the unhash_offsprings() thing. I've cc'd > Lukas who is probably more familiar with this code. > > FWIW, I suspect the more you can elaborate on what the backup > application might be doing here (beyond just the rm -rf), the more > likely this can be reproduced and resolved. Hi the lockdep warning should be fixed in the recent rhel6 kernel. Sorry about that. -Lukas > > Brian > > > > > > > Brian > > > > > > > > > > -- > > Grant Keller > > System Operations > > 707-237-2451 > > grant.keller@xxxxxxxxx > > > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
