WARNING: CPU: 1 PID: 1384 at lib/iov_iter.c:695 copy_page_to_iter+0x240/0x3b0

From: Christian Kujau
Date: Sun Dec 24 2017 - 04:36:47 EST


this just happened on an i686 machine of mine:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 1384 at lib/iov_iter.c:695 copy_page_to_iter+0x240/0x3b0
Modules linked in: xfs algif_skcipher af_alg uas nfsv4 dns_resolver nfs
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_meta
nf_conntrack_ipv6 nf_defrag_ipv6 nf_conntrack_ipv4 lz4 nf_defrag_ipv4
lz4_compress nft_ct nf_conntrack libcrc32c crc32c_generic nft_set_hash
nf_tables_inet nf_tables_ipv6 nf_tables_ipv4 nf_tables nfnetlink
cpufreq_conservative sch_fq_codel zram evdev tg3 ptp pps_core lpc_ich
libphy input_leds ideapad_laptop sparse_keymap wmi serpent_sse2_i586
thermal serpent_generic lrw glue_helper ablk_helper cryptd video xts
dm_crypt acpi_cpufreq arc4 iTCO_wdt iTCO_vendor_support i2c_i801 fscache
loop coretemp battery b43 bcma mac80211 cfg80211 dm_mod dax ssb mmc_core
rfkill led_class rng_core pcmcia pcmcia_core nfsd auth_rpcgss oid_registry
ac nfs_acl lockd grace
sunrpc usb_storage sd_mod atkbd libps2 uhci_hcd ata_piix libata scsi_mod
ehci_pci ehci_hcd usbcore usb_common i8042 serio jfs [last unloaded:
CPU: 1 PID: 1384 Comm: java Not tainted 4.14.4-1.0-ARCH #1
Hardware name: LENOVO Lenovo /Mariana , BIOS 14CN94WW 06/29/2009
task: f27c1380 task.stack: f1c64000
EIP: copy_page_to_iter+0x240/0x3b0
EFLAGS: 00010286 CPU: 1
EAX: 00001000 EBX: ffb48000 ECX: 000002c0 EDX: 8001006c
ESI: f67ecb60 EDI: 00000d40 EBP: f1c65e30 ESP: f1c65e08
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 80050033 CR2: 09f060cc CR3: 3260f000 CR4: 000006d0
Call Trace:
? touch_atime+0x2b/0xb0
? xfs_ilock+0x10d/0x150 [xfs]
? xfs_file_buffered_aio_read+0xed/0x100 [xfs]
xfs_file_buffered_aio_read+0x4e/0x100 [xfs]
? set_next_entity+0x13f/0x8b0
xfs_file_read_iter+0x54/0xc0 [xfs]
EIP: 0xb7f69cd9
EFLAGS: 00000293 CPU: 1
EAX: ffffffda EBX: 0000009b ECX: 23c77f10 EDX: 0000001a
ESI: 156172c0 EDI: 00000000 EBP: b7f50e70 ESP: 1f32ea60
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
Code: 75 ec e9 ff fe ff ff 8d 74 26 00 8b 55 ec 8b 45 08 85 d2 8b 58 0c 74
09 e8 6e d7 ff ff 84 c0 75 1a 31 f6 e9 13 ff ff ff 8d 76 00 <0f> ff 31 f6
83 c4 1c 5b 89 f0 5e 5f 5d c3 66 90 8b 7d 08 8b 45
---[ end trace 0002deba6d00a28c ]---

This i686 laptop is running 4.14.4-1.0-ARCH [0] and is usually running
just fine, although memory pressure is usually quite hight due to some
Java program running on that machine. For some reason the system was even
more busy today, commands would take a long time to complete and I
rebooted the machine. Shortly after boot (and after starting this Java
program again), the warning above happened.

I couldn't find this exact message in the archives, the closest thing I
found was (mentioning that "EIP:copy_page_to_iter" message):

> 4879b7ae05 ("Merge tag 'dmaengine-4.12-rc1' of .."): WARNING: kernel
> stack regs at bd92bc2e in 01-cpu-hotplug:3811 has bad 'bp' value 000001be
> https://patchwork.kernel.org/patch/9981273/

The XFS file system is mounted with:

> XFS (dm-2): EXPERIMENTAL reverse mapping btree feature enabled. Use at your own risk!
> XFS (dm-2): EXPERIMENTAL reflink feature enabled. Use at your own risk!

But I did not experience any problems with that, yet :)

Full dmesg & .config: http://nerdbynature.de/bits/4.14/

Any pointers?


$ mount | grep xfs
/dev/mapper/opt on /opt type xfs (rw,nosuid,nodev,relatime,attr2,inode64,noquota)

$ xfs_info /opt/
meta-data=/dev/mapper/opt isize=512 agcount=4, agsize=9079797
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1 spinodes=0 rmapbt=1
= reflink=1
data = bsize=4096 blocks=36319185, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=17733, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0

[0] https://mirror.archlinux32.org/i686/core/linux-4.14.4-1.0-i686.pkg.tar.xz
BOFH excuse #413:

Cow-tippers tipped a cow onto the server.