[OOPS] hugetlbfs tests with 2.6.30-rc8-git1

Sachin Sant sachinp at in.ibm.com
Mon Jun 15 23:00:30 EST 2009


Michael Ellerman wrote:
> Hi Sachin,
>
> Rather than "-git7" can you tell us the actual SHA, I don't know what
> git7 is.
>   
Corresponding SHA is 44b7532b8b464f606053562400719c9c21276037.

>> Here is the supporting data.
>>
>>  cpu 0x1: Vector: 300 (Data Access) at [c0000000fe9b3220]
>>     pc: c00000000003d620: .hpte_need_flush+0x1bc/0x2d8
>>     lr: c00000000003d4d0: .hpte_need_flush+0x6c/0x2d8
>>     sp: c0000000fe9b34a0
>>    msr: 8000000000009032
>>    dar: c0000000283b0d78
>>     
>
> This address looks pretty innocuous, but I notice you have
> DEBUG_PAGEALLOC=y, so presumably that's why it's triggering.
>
> I can't see from the snippet of disassembly you posted where in the C
> code we are, can you work it out?
>   
The corresponding C code is :

 278:   2f 80 00 00     cmpwi   cr7,r0,0
        } else {
                vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
                ssize = mmu_kernel_ssize;
        }
        vaddr = hpt_va(addr, vsid, ssize);
        rpte = __real_pte(__pte(pte), ptep);
 27c:   eb 89 80 00     ld      r28,-32768(r9)  
^^^^ %pc points to the above line. ^^^^^
         * Check if we have an active batch on this CPU. If not, just
         * flush now and return. For now, we don global invalidates
         * in that case, might be worth testing the mm cpu mask though
         * and decide to use local invalidates instead...

I have attached the objdump o/p for tlb_hash64.o.

I could not recreate this issue with git8 kernel
(45e3e1935e2857c54783291107d33323b3ef33c8).

Thanks
-Sachin

-- 

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

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