[powerpc] Next tree Nov 2 : kernel BUG at mm/mmap.c:2135!

[Sachin Sant]

Sachin Sant wrote:
> Today's next tree failed to boot on a POWER 6 box with :
>
> ------------[ cut here ]------------
> kernel BUG at mm/mmap.c:2135!
> Oops: Exception in kernel mode, sig: 5 [#2]
> SMP NR_CPUS=1024 NUMA pSeries
Problem exists with today's next as well.

Likely cause for this problem seems to the following commit.
If i revert this patch the machine boots fine.

commit a0668cdc154e54bf0c85182e0535eea237d53146
powerpc/mm: Cleanup management of kmem_caches for pagetables

Thanks
-Sachin

> Modules linked in: ibmvscsic scsi_transport_srp scsi_tgt scsi_mod
> NIP: c00000000014e30c LR: c00000000014e2f8 CTR: c00000000014db88
> REGS: c0000000db703620 TRAP: 0700   Tainted: G      D     
> (2.6.32-rc5-autotest-next-20091102)
> MSR: 8000000000029032 <EE,ME,CE,IR,DR>  CR: 24022442  XER: 2000000c
> TASK = c0000000db7f6fe0[76] 'init' THREAD: c0000000db700000 CPU: 1
> GPR00: 0000000000000001 c0000000db7038a0 c000000000b19900 
> 0000000000000000
> GPR04: c0000000db406a40 000000000000000c c0000000fe10c370 
> c000000000bb2800
> GPR08: 000000000000db40 0000000000000000 c0000000dfdc0e00 
> 000000000000000c
> GPR12: 0000000044022442 c000000000bb2800 00000000ffffffff 
> ffffffffffffffff
> GPR16: 0000000008430000 00000000003c0000 c0000000db703ea0 
> c0000000db569108
> GPR20: c0000000db568908 0000000000000000 c0000000db703d60 
> 0000000000000000
> GPR24: 0000000000000001 0000000000040100 c0000000fe503580 
> c0000000db1ac180
> GPR28: 0000000000000000 c000000000f812d0 c000000000a84f00 
> 0000000000000000
> NIP [c00000000014e30c] .exit_mmap+0x190/0x1b8
> LR [c00000000014e2f8] .exit_mmap+0x17c/0x1b8
> Call Trace:
> [c0000000db7038a0] [c00000000014e2f8] .exit_mmap+0x17c/0x1b8 (unreliable)
> [c0000000db703950] [c0000000000916cc] .mmput+0x54/0x164
> [c0000000db7039e0] [c0000000000968d8] .exit_mm+0x17c/0x1a0
> [c0000000db703a90] [c000000000098cb8] .do_exit+0x248/0x784
> [c0000000db703b70] [c0000000000992a8] .do_group_exit+0xb4/0xe8
> [c0000000db703c00] [c0000000000aca2c] .get_signal_to_deliver+0x3ec/0x478
> [c0000000db703cf0] [c0000000000134ac] .do_signal+0x6c/0x31c
> [c0000000db703e30] [c000000000008b7c] do_work+0x24/0x28
> Instruction dump:
> 7c8407b4 387d0018 4800ab11 60000000 939d0008 7fe3fb78 4bfffdbd 7c7f1b79
> 4082fff4 e81b00e8 3120ffff 7c090110 <0b000000> 382100b0 e8010010 eb61ffd8
> ---[ end trace ec052ac77a8e7cb4 ]---
> Fixing recursive fault but reboot is needed!
>
> mm/mmap.c:2135 corresponds to :
>
> BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
>

-- 

---------------------------------
Sachin Sant
IBM Linux Technology Center
India Systems and Technology Labs
Bangalore, India
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