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

From: Waiman Long
Date: Tue Apr 21 2015 - 16:52:49 EST


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.

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

Cheers,
Longman


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