Comment 21 for bug 1724120

------- Comment From <email address hidden> 2018-01-23 09:23 EDT-------
Hi Joseph,

I was able to reproduce the problem on HWE Kernal (XENIAL):

-- System

root@tuletapio2-lp3:~# uname -a
Linux tuletapio2-lp3 4.13.13 #1 SMP Tue Jan 23 07:41:39 CST 2018 ppc64le ppc64le ppc64le GNU/Linux

root@tuletapio2-lp3:~# cat /proc/meminfo
HugePages_Total: 2
HugePages_Free: 2
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 16777216 kB

root@tuletapio2-lp3:~# cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinux-4.13.13 root=UUID=728bebfe-83ba-410d-917b-b552edbbb0a3 ro quiet splash default_hugepagesz=16G hugepagesz=16G hugepages=2

-- DUMP
Unable to handle kernel paging request for data at address 0x5deadbeef0000108
Faulting instruction address: 0xc0000000002cf374
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2048
NUMA
pSeries
Modules linked in:
CPU: 7 PID: 3769 Comm: mem-on-off-test Not tainted 4.13.13 #1
task: c0000007d9400000 task.stack: c0000007d9480000
NIP: c0000000002cf374 LR: c0000000002cf298 CTR: c000000000134ef0
REGS: c0000007d94837d0 TRAP: 0380 Not tainted (4.13.13)
MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>
CR: 44422484 XER: 00000000
CFAR: c0000000002cf308 SOFTE: 1
GPR00: c0000000002cf28c c0000007d9483a50 c000000000e6ff00 c000000000fbc580
GPR04: f000000004000000 5deadbeef0000100 5deadbeef0000200 0000000000000002
GPR08: 5deadbeef0000000 0000000000000001 c000000000fbc580 c0000007fb000628
GPR12: 0000000000002200 c00000000fd02a00 0000000000001000 f000000004000000
GPR16: 0000000000000002 0000000000000000 c000000000ea3b00 0000000000001000
GPR20: 00000000ffffdb4f 0000000000000001 c000000fffd44600 c0000007d9483b60
GPR24: 0000000000100000 c000000000f0dad8 c000000000eb2dd0 0000000000000001
GPR28: 0000000000000000 c000000000fc4580 c000000000fd4580 f000000004000000
NIP [c0000000002cf374] dissolve_free_huge_page+0x124/0x230
LR [c0000000002cf298] dissolve_free_huge_page+0x48/0x230
Call Trace:
[c0000007d9483a50] [c0000000002cf28c] dissolve_free_huge_page+0x3c/0x230 (unreliable)
[c0000007d9483a90] [c0000000002cf548] dissolve_free_huge_pages+0xc8/0x150
[c0000007d9483ae0] [c0000000002ee1c8] __offline_pages.constprop.5+0x398/0xa90
[c0000007d9483c30] [c000000000645870] memory_subsys_offline+0x60/0xf0
[c0000007d9483c60] [c000000000623434] device_offline+0xf4/0x130
[c0000007d9483ca0] [c000000000645718] store_mem_state+0x178/0x190
[c0000007d9483ce0] [c00000000061ea34] dev_attr_store+0x34/0x60
[c0000007d9483d00] [c0000000003bdd10] sysfs_kf_write+0x60/0xa0
[c0000007d9483d20] [c0000000003bcaac] kernfs_fop_write+0x16c/0x240
[c0000007d9483d70] [c000000000314cf4] __vfs_write+0x34/0x70
[c0000007d9483d90] [c00000000031673c] vfs_write+0xcc/0x230
[c0000007d9483de0] [c000000000318410] SyS_write+0x60/0x110
[c0000007d9483e30] [c00000000000b860] system_call+0x58/0x6c
Instruction dump:
e90a0030 88ff0007 7fa94000 419e0120 3d005dea e8df0028 e8bf0020 7fe4fb78
6108dbee 7d435378 790807c6 6508f000 <f8c50008> f8a60000 7d094378 61080100
---[ end trace 23e3dda3fe0a58bd ]--