Subject: [BUG] [PowerPC] Kernel Oops when booting Linux mainline

From: Abdul Haleem <[email-masked]>
Date: Mon, 13 Mar 2017 14:48:35 +0530

Hi,

Mainline boot is broken on PowerPC bare metal with below traces:
Machine Type : Power 8 Bare metal

[  OK  ] Mounted Debug File System.
[  OK  ] Started Nameserver information manager.
[  OK  ] Started LVM2 metadata daemon.
Unable to handle kernel paging request for data at address 0x300000079
Faulting instruction address: 0xc000000000811cac
Oops: Kernel access of bad area, sig: 11 [#1]
Unable to handle kernel paging request for instruction fetch
Unable to handle kernel paging request for data at address 0xc000007c77881e28
Faulting instruction address: 0xc000003c7acd7b80
Faulting instruction address: 0xc00000000029fd88
Thread overran stack, or stack corrupted
SMP NR_CPUS=2048 
NUMA 
PowerNV
Modules linked in: ip_table�KK~<(E) x_tables�\8|<(E) autofs4(E) raid10 raid456 async_raid6_recov 
async_memcpy async_pq async_xor async_tx xor raid6_pq multipath bnx2x(E) mdio(E) libcrc32�^B�w<(E)
CPU: 21 PID: 137 Comm: kworker/21:0 Not tainted 4.11.0-rc1-00335-g56b24d1-dirty #1
Workqueue: events dbs_work_handler
task: c000003c8e86b380 task.stack: c000003c8eae0000
NIP: c000000000811cac LR: c000000000813014 CTR: c000000000811c50
REGS: c000003c8eae3980 TRAP: 0300   Not tainted  (4.11.0-rc1-00335-g56b24d1-dirty)
MSR: 900000010280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]>
  CR: 24002422  XER: 00000000  
CFAR: c000000000008860 DAR: 0000000300000079 DSISR: 40000000 SOFTE: 1 
GPR00: c000000000813014 c000003c8eae3c00 c000000001019800 c000003c780d0800 
GPR04: 0000000000000540 0000000000000000 0000000000000000 c000003c8e86b380 
GPR08: 0000000000000000 000000000000003c 000000000000003c 0000000000008397 
GPR12: c000000000811c50 c00000000fe05400 c0000000000f2e08 c000003ffb073d80 
GPR16: c000003ffc564328 c000003ffc5640f8 c000003ffc5640a0 0000000000000001 
GPR20: 0000000000000000 0000000000000000 c000000000f50bc0 fffffffffffffef7 
GPR24: 0000000000000000 c000003ffc564400 0000000000000000 0000000300000001 
GPR28: c000003c780d0b60 0000000300000001 c000003c780d0800 c000003c780d0b60 
NIP [c000000000811cac] od_dbs_update+0x5c/0x260
LR [c000000000813014] dbs_work_handler+0x54/0xa0
Call Trace:
[c000003c8eae3c00] [c000003ffc564880] 0xc000003ffc564880 (unreliable)
[c000003c8eae3c50] [c000000000813014] dbs_work_handler+0x54/0xa0
[c000003c8eae3c90] [c0000000000ea600] process_one_work+0x2a0/0x590
[c000003c8eae3d20] [c0000000000ea998] worker_thread+0xa8/0x660
[c000003c8eae3dc0] [c0000000000f2f4c] kthread+0x14c/0x190
[c000003c8eae3e30] [c00000000000b4e8] ret_from_kernel_thread+0x5c/0x74
Instruction dump:
f821ffb1 ebe30340 813f00ac 895f00ac ebbf0078 71280001 5549003c 993f00ac 
40820164 eb9e0340 7fc3f378 eb7c0078 <eb5b0078> 48001539 60000000 39200000 
---[ end trace 587e7f5a13c0f2ad ]---

Detailed logs and config is attached.

FYI, Good commit of last successful boot is : 

commit ea6200e84182989a3cce9687cf79a23ac44ec4db
Merge: b4fb8f6 fc69910
Author: Linus Torvalds <[email-masked]>
Date:   Wed Mar 8 14:45:31 2017 -0800

    Merge branch 'core-urgent-for-linus' of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

-- 
Regard's

Abdul Haleem
IBM Linux Technology Centre