Re: [BUG] 2.6.25-rc2-git4 - Regression Kernel oops while running kernbench and tbench on powerpc

Kamalesh Babulal writes:

The kernel oops after applying the patch. Some time it takes more than
one run to reproduce it, it was reproducible in the second run this
time.

 Unrecoverable exception 4100 at c000000000008c8c
Oops: Unrecoverable exception, sig: 6 [#1]
SMP NR_CPUS=128 NUMA pSeries
Modules linked in:
NIP: c000000000008c8c LR: 000000000ff0135c CTR: 000000000ff012f0
REGS: c000000772343bb0 TRAP: 4100   Not tainted  (2.6.25-rc8-autotest)
MSR: 8000000000001030 <ME,IR,DR>  CR: 44044228  XER: 00000000
TASK = c00000077cfa0900[13437] 'cc1' THREAD: c000000772340000 CPU: 2
GPR00: 0000000000004000 c000000772343e30 00000000000000bb 000000000000d032 
GPR04: 00000000000000bb 0000000000000400 000000000000000a 0000000000000002 
GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
GPR12: 0000000000000000 c000000000734000 0000000000000064 00000000ffe6df08 
GPR16: 00000000105b0000 00000000105b0000 0000000010440000 00000000105b0000 
GPR20: 00000000ffe6e008 00000000105b0000 00000000105b0000 000000000000000a 
GPR24: 000000000ffec408 0000000000000001 00000000ffe6ddca 0000000000000400 
GPR28: 000000000ffec408 00000000f7ff8000 000000000ffebff4 0000000000000400 
NIP [c000000000008c8c] restore+0x8c/0xc0
LR [000000000ff0135c] 0xff0135c
Call Trace:
[c000000772343e30] [c000000000008cd4] do_work+0x14/0x2c (unreliable)
Instruction dump:
7c840078 7c810164 70604000 41820028 60000000 7c4c42e6 e88d01f0 f84d01f0 
7c841050 e84d01e8 7c422214 f84d01e8 <e9a100d8> 7c7b03a6 e84101a0 7c4ff120 

(gdb) l *0xc000000000008cdc
0xc000000000008cdc is at arch/powerpc/kernel/entry_64.S:608.
603             mtmsrd  r10,1
604
605             andi.   r0,r4,_TIF_NEED_RESCHED
606             beq     1f
607             bl      .schedule
608             b       .ret_from_except_lite
609
610     1:      bl      .save_nvgprs
611             li      r3,0
612             addi    r4,r1,STACK_FRAME_OVERHEAD

The exception happened at c...8c8c but you looked at c...8cdc with
gdb.  What's at c...8c8c?

please let me know if you need more information.

The .config would be useful, but don't spam everyone on cc with it,
just send it to me privately.

Paul.