Comment 6 for bug 1758206

------- Comment From <email address hidden> 2018-03-29 11:31 EDT-------
(In reply to comment #10)
> I built a Bionic test kernel with the three commits mentioned in the bug
> description. The test kernel can be downloaded from:
> http://kernel.ubuntu.com/~jsalisbury/lp1758206
>
> Can you test this kernel and see if it resolves this bug?
>
> Note, to test this kernel, you need to install both the linux-image and
> linux-image-extra .deb packages.
>
> Thanks in advance!

Tried with given kernel, kexec still failed. Please find logs below.

root@ltc-wspoon4:~# ppc64_cpu --smt
SMT is off
root@ltc-wspoon4:~# kdump-config show
DUMP_MODE: kdump
USE_KDUMP: 1
KDUMP_SYSCTL: kernel.panic_on_oops=1
KDUMP_COREDIR: /var/crash
crashkernel addr:
/var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinux-4.15.0-12-generic
kdump initrd:
/var/lib/kdump/initrd.img: symbolic link to /var/lib/kdump/initrd.img-4.15.0-12-generic
current state: ready to kdump

kexec command:
/sbin/kexec -p --command-line="root=UUID=0266024d-8ea3-4132-ad62-b49befd6f8d9 ro quiet splash nr_cpus=1 systemd.unit=kdump-tools.service irqpoll noirqdistrib nousb" --initrd=/var/lib/kdump/initrd.img /var/lib/kdump/vmlinuz
root@ltc-wspoon4:~# echo "c" > /proc/sysrq-trigger
[ 951.567597] sysrq: SysRq : This sysrq operation is disabled.
root@ltc-wspoon4:~# echo 1 > /proc/sys/kernel/sysrq
root@ltc-wspoon4:~# echo "c" > /proc/sysrq-trigger
[ 968.396522] sysrq: SysRq : Trigger a crash
[ 968.396558] Unable to handle kernel paging request for data at address 0x00000000
[ 968.396602] Faulting instruction address: 0xc0000000007ec768
[ 968.396640] Oops: Kernel access of bad area, sig: 11 [#1]
[ 968.396670] LE SMP NR_CPUS=2048 NUMA PowerNV
[ 968.396703] Modules linked in: idt_89hpesx(E) at24 uio_pdrv_genirq ofpart cmdlinepart powernv_flash mtd uio ibmpowernv ipmi_powernv vmx_crypto ipmi_devintf ipmi_msghandler opal_prd crct10dif_vpmsum sch_fq_codel ip_tables x_tables autofs4 ast i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ahci crc32c_vpmsum drm tg3 libahci
[ 968.396893] CPU: 28 PID: 3086 Comm: bash Tainted: G E 4.15.0-12-generic #13~lp1758206
[ 968.396944] NIP: c0000000007ec768 LR: c0000000007ed6a8 CTR: c0000000007ec740
[ 968.396989] REGS: c0000000054fb9f0 TRAP: 0300 Tainted: G E (4.15.0-12-generic)
[ 968.397040] MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 28222222 XER: 20040000
[ 968.397090] CFAR: c0000000007ed6a4 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 1
[ 968.397090] GPR00: c0000000007ed6a8 c0000000054fbc70 c0000000016eaf00 0000000000000063
[ 968.397090] GPR04: c000001ff76bce18 c000001ff76d4368 9000000000009033 000000000000000a
[ 968.397090] GPR08: 0000000000000007 0000000000000001 0000000000000000 9000000000001003
[ 968.397090] GPR12: c0000000007ec740 c000000007a33400 00000a463c88ae48 0000000000000000
[ 968.397090] GPR16: 00000a462439e9f0 00000a4624431998 00000a46244319d0 00000a4624468204
[ 968.397090] GPR20: 0000000000000000 0000000000000001 0000000000000000 00007ffff9ecd164
[ 968.397090] GPR24: 00007ffff9ecd160 00000a462446afc4 c0000000015e9968 0000000000000002
[ 968.397090] GPR28: 0000000000000063 0000000000000007 c000000001572a9c c0000000015e9d08
[ 968.397486] NIP [c0000000007ec768] sysrq_handle_crash+0x28/0x30
[ 968.397524] LR [c0000000007ed6a8] __handle_sysrq+0xf8/0x2c0
[ 968.397554] Call Trace:
[ 968.397571] [c0000000054fbc70] [c0000000007ed688] __handle_sysrq+0xd8/0x2c0 (unreliable)
[ 968.397618] [c0000000054fbd10] [c0000000007edeb4] write_sysrq_trigger+0x64/0x90
[ 968.397664] [c0000000054fbd40] [c00000000047dfe8] proc_reg_write+0x88/0xd0
[ 968.397703] [c0000000054fbd70] [c0000000003d131c] __vfs_write+0x3c/0x70
[ 968.397742] [c0000000054fbd90] [c0000000003d1578] vfs_write+0xd8/0x220
[ 968.397781] [c0000000054fbde0] [c0000000003d1898] SyS_write+0x68/0x110
[ 968.397821] [c0000000054fbe30] [c00000000000b184] system_call+0x58/0x6c
[ 968.397857] Instruction dump:
[ 968.397881] 4bfff9f1 4bfffe50 3c4c00f0 3842e7c0 7c0802a6 60000000 39200001 3d42001c
[ 968.397929] 394a6db0 912a0000 7c0004ac 39400000 <992a0000> 4e800020 3c4c00f0 3842e790
[ 968.397979] ---[ end trace 42b5936ebd77f0df ]---
[ 969.403420]
[ 969.403499] Sending IPI to other CPUs
[ 970.[ 9304.282854548,5] OPAL: Switch to big-endian OS
699527] IPI c[ 9308.106771743,5] OPAL: Switch to little-endian OS
[ 9309.438684420,3] PHB#0000[0:0]: CRESET: Unexpected slot state 00000102, resetting...
[ 9310.039758053,3] PHB#0000[0:0]: Timeout waiting for DLP PG reset !
[ 9310.039836165,3] PHB#0000[0:0]: Initialization failed
[ 9312.102310864,3] PHB#0001[0:1]: Timeout waiting for DLP PG reset !
[ 9312.102386083,3] PHB#0001[0:1]: Initialization failed
[ 9314.164868252,3] PHB#0002[0:2]: Timeout waiting for DLP PG reset !
[ 9314.165418307,3] PHB#0002[0:2]: Initialization failed
[ 9316.116455526,3] PHB#0003[0:3]: CRESET: Unexpected slot state 00000102, resetting...
[ 9316.229566014,3] PHB#0003[0:3]: Timeout waiting for DLP PG reset !
[ 9316.229647769,3] PHB#0003[0:3]: Initialization failed
[ 9318.292115865,3] PHB#0004[0:4]: Timeout waiting for DLP PG reset !
[ 9318.294132075,3] PHB#0004[0:4]: Initialization failed
[ 9320.356607557,3] PHB#0005[0:5]: Timeout waiting for DLP PG reset !
[ 9320.357808219,3] PHB#0005[0:5]: Initialization failed
[ 9322.308528728,3] PHB#0030[8:0]: CRESET: Unexpected slot state 00000102, resetting...
[ 9322.421406022,3] PHB#0030[8:0]: Timeout waiting for DLP PG reset !
[ 9322.422552792,3] PHB#0030[8:0]: Initialization failed
[ 9324.372530715,3] PHB#0033[8:3]: CRESET: Unexpected slot state 00000102, resetting...
[ 9324.485399371,3] PHB#0033[8:3]: Timeout waiting for DLP PG reset !
[ 9324.485730350,3] PHB#0033[8:3]: Initialization failed
[ 9326.436229911,3] PHB#0034[8:4]: CRESET: Unexpected slot state 00000102, resetting...
[ 9328.510462286,3] PHB#0035[8:5]: Timeout waiting for DLP PG reset !
[ 9328.511713428,3] PHB#0035[8:5]: Initialization failed
omplete
[ 972.402103] kexec: Starting switchover sequence.
[ 0.753802] integrity: Unable to open file: /etc/keys/x509_ima.der (-2)
[ 0.753808] integrity: Unable to open file: /etc/keys/x509_evm.der (-2)
[ 0.830129] vio vio: uevent: failed to send synthetic uevent

Gave up waiting for root file system device. Common problems:
- Boot args (cat /proc/cmdline)
- Check rootdelay= (did the system wait long enough?)
- Missing modules (cat /proc/modules; ls /dev)
ALERT! UUID=0266024d-8ea3-4132-ad62-b49befd6f8d9 does not exist. Dropping to a shell!

BusyBox v1.27.2 (Ubuntu 1:1.27.2-2ubuntu3) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs)
(initramfs)
(initramfs)
(initramfs)
(initramfs)