Re: 4.0 kernel XFS filesystem crash when running AIM7's disk workload

[Dave Chinner]

On Tue, Apr 21, 2015 at 04:52:37PM -0400, Waiman Long wrote:
> On 04/17/2015 07:45 PM, Dave Chinner wrote:
> >On Fri, Apr 17, 2015 at 01:38:49PM -0400, Waiman Long wrote:
> >>Hi Dave,
> >>
> >>When I was running the AIM7's disk workload on a 8-socket
> >>Westmere-EX server with 4.0 kernel, the kernel crash. A set of small
> >>ramdisks were created (ramdisk_size=271072). Those ramdisks were
> >>formatted with XFS filesystem before the test began. The kernel log
> >>was:
> >>
> >>XFS (ram12): Mounting V4 Filesystem
> >>XFS (ram12): Log size 1424 blocks too small, minimum size is 1596 blocks
> >>XFS (ram12): Log size out of supported range. Continuing onwards,
> >>but if log hangs are
> >>experienced then please report this message in the bug report.
> >First thing you need to do is upgrade xfsprogs so that this message
> >goes away. or use "mkfs.xfs -l size=10m" so that the log is larger
> >than the minimum.
> >
> >>XFS (ram15): Ending clean mount
> >>BUG: unable to handle kernel NULL pointer dereference at           (null)
> >>IP: [<ffffffff812abd6d>] __memcpy+0xd/0x110
> >>PGD 29f7655f067 PUD 29f75a80067 PMD 0
> >>Oops: 0000 [#1] SMP
> >>Modules linked in: xfs exportfs libcrc32c ebtable_nat ebtables
> >>xt_CHECKSUM iptable_mangle bridge stp llc autofs4 ipt_REJECT
> >>nf_reject_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter
> >>ip_tables ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
> >>nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6
> >>vhost_net macvtap macvlan vhost tun kvm_intel kvm ipmi_si
> >>ipmi_msghandler tpm_infineon iTCO_wdt iTCO_vendor_support wmi
> >>acpi_cpufreq microcode pcspkr serio_raw qlcnic be2net vxlan
> >>udp_tunnel ip6_udp_tunnel ses enclosure igb dca ptp pps_core lpc_ich
> >>mfd_core hpilo hpwdt sg i7core_edac edac_core netxen_nic ext4(E)
> >>jbd2(E) mbcache(E) sr_mod(E) cdrom(E) sd_mod(E) lpfc(E) qla2xxx(E)
> >>scsi_transport_fc(E) pata_acpi(E) ata_generic(E) ata_piix(E) hpsa(E)
> >>radeon(E) ttm(E) drm_kms_helper(E) drm(E) i2c_algo_bit(E)
> >>i2c_core(E) dm_mirror(E) dm_region_hash(E) dm_log(E) dm_mod(E)
> >Why do you have a mix of signed and unsigned modules loaded?
> 
> I did the test on a RHEL 6.6 system. The 4.0 kernel is unsigned, but
> there are some additional RHEL modules loaded at boot up time.

Wait, what?

Do you have rhel 6.6 modules loaded into a 4.0 kernel? If so, I'd
suggest you fix things so that doesn't happen before running any
more tests...

> >>CPU: 69 PID: 116603 Comm: xfsaild/ram5 Tainted: G            E   4.0.0 #2
> >>Hardware name: HP ProLiant DL980 G7, BIOS P66 07/30/2012
> >>task: ffff8b9f7eeb4f80 ti: ffff8b9f7f1ac000 task.ti: ffff8b9f7f1ac000
> >>RIP: 0010:[<ffffffff812abd6d>]  [<ffffffff812abd6d>] __memcpy+0xd/0x110
> >>RSP: 0018:ffff8b9f7f1afc10  EFLAGS: 00010206
> >>RAX: ffff88102476a3cc RBX: ffff889ff2ab5000 RCX: 0000000000000005
> >>RDX: 0000000000000006 RSI: 0000000000000000 RDI: ffff88102476a3cc
> >edx = 6 bytes.
> >
> >>RBP: ffff8b9f7f1afc18 R08: 0000000000000001 R09: ffff88102476a3cc
> >>R10: ffff8a1f6c03ea80 R11: 0000000000000000 R12: ffff8b1ff1269400
> >>R13: ffff8b1f64837c98 R14: ffff881038701200 R15: ffff88102476a300
> >>FS:  0000000000000000(0000) GS:ffff8b1fffa40000(0000) knlGS:0000000000000000
> >>CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> >>CR2: 0000000000000000 CR3: 0000029f7655e000 CR4: 00000000000006e0
> >>Stack:
> >>  ffffffffa0ca8c41 ffff8b9f7f1afc68 ffffffffa0cc4803 ffff8b9f7f1afc68
> >>  ffffffffa0cd2777 ffff8b9f7f1afc68 ffff8b1ff1269400 ffff8a9f59022800
> >>  ffff8b1f7c932718 0000000000000003 ffff8a9f590228e4 ffff8b9f7f1afce8
> >>Call Trace:
> >>  [<ffffffffa0ca8c41>] ? xfs_iflush_fork+0x181/0x240 [xfs]
> >>  [<ffffffffa0cc4803>] xfs_iflush_int+0x1f3/0x320 [xfs]
> >>  [<ffffffffa0cd2777>] ? kmem_alloc+0x87/0x100 [xfs]
> >>  [<ffffffffa0cc60a5>] xfs_iflush_cluster+0x295/0x380 [xfs]
> >>  [<ffffffffa0cc8ff4>] xfs_iflush+0xf4/0x1f0 [xfs]
> >>  [<ffffffffa0cda22a>] xfs_inode_item_push+0xea/0x130 [xfs]
> >>  [<ffffffffa0ce140d>] xfsaild_push+0x10d/0x500 [xfs]
> >>  [<ffffffff810b7c20>] ? lock_timer_base+0x70/0x70
> >>  [<ffffffffa0ce1898>] xfsaild+0x98/0x130 [xfs]
> >>  [<ffffffffa0ce1800>] ? xfsaild_push+0x500/0x500 [xfs]
> >>  [<ffffffffa0ce1800>] ? xfsaild_push+0x500/0x500 [xfs]
> >>  [<ffffffffa0ce1800>] ? xfsaild_push+0x500/0x500 [xfs]
> >>  [<ffffffff81074b50>] ? kthread_freezable_should_stop+0x70/0x70
> >>  [<ffffffff815c5748>] ret_from_fork+0x58/0x90
> >>  [<ffffffff81074b50>] ? kthread_freezable_should_stop+0x70/0x70
> >>Code: 0f b6 c0 5b c9 c3 0f 1f 84 00 00 00 00 00 e8 2b f9 ff ff 80 7b
> >>25 00 74 c8 eb d3 90 90 90 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07
> >><f3>  48 a5 89 d1 f3 a4 c3 20 4c 8b 06 4c 8b 4e 08 4c 8b 56 10 4c
> >>RIP  [<ffffffff812abd6d>] __memcpy+0xd/0x110
> >>  RSP<ffff8b9f7f1afc10>
> >>CR2: 0000000000000000
> >>---[ end trace fb8a4add69562a76 ]---
> >>
> >>The xfs_iflush_fork+0x181/0x240 (385) IP address is at:
> >>
> >(rearrange slightly to make more sense)
> >
> >>823        case XFS_DINODE_FMT_LOCAL:
> >>824            if ((iip->ili_fields&  dataflag[whichfork])&&
> >>    0x00000000000023c0<+336>:    movslq %ecx,%rcx
> >>    0x00000000000023c3<+339>:    movswl 0x0(%rcx,%rcx,1),%eax
> >>    0x00000000000023cb<+347>:    test   %eax,0x90(%rdx)
> >>    0x00000000000023d1<+353>:    je     0x2350<xfs_iflush_fork+224>
> >>
> >>825                (ifp->if_bytes>  0)) {
> >>    0x00000000000023d7<+359>:    mov    (%r10),%edx
> >>    0x00000000000023da<+362>:    test   %edx,%edx
> >>    0x00000000000023dc<+364>:    jle    0x2350<xfs_iflush_fork+224>
> >So the contents of rdx says that the inode fork size is 6 bytes in
> >local format. The call location also indicates that it is the
> >attribute fork that is in being flushed. The minimum size of the
> >attr fork is 3 bytes - an empty header. However, then ext valid size
> >has a second header that adds 4 bytes to the size, plus the bytes
> >inteh attr name and value.
> >
> >Hence a size of 6 bytes is invalid, and probably indicates that
> >there is some form of memory corruption going on here.
> >
> >IIRC, we haven't touched this code for a while - can you test 3.19
> >and see if it has the same problem? If it doesn't have the problem,
> >and given you can reliably reproduce the crash, can you run a
> >bisect to find the cause?
> 
> I have done the bisection and the following commit in 3.13 is the
> one that cause the problem, I think:
> 
> f7be2d7f594cbc7a00902b5427332a1ad519a528
> xfs: push down inactive transaction mgmt for truncate
> 
> I looked at the patch, and it didn't seem quite right,

In what way?

> but I don't
> know much about the XFS internal to be sure. Maybe you can take a
> look at that.

Doesn't actually seem very likely - that's mostly just a factoring
patch, and it is called on every inode that is reclaimed from
memory, so it's not like that code path doesn't get well tested....

So, I'm confused - I thought you were reporting a recent regression.
Are you actually reporting a regression between a RHEL 6.6 kernel
and the current mainline kernel?  Is this the first time you've run
this test on XFS on a kernel more recent than RHEL6.6?

Details, please; they are important.

http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
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