[BUG/REGRESSION] Kernel 4.5-rc1 on Acube Sam460ex AMCC 460ex Power PC motherboards

Julian Margetson runaway at candw.ms
Thu Jan 28 10:21:48 PST 2016


On 1/28/2016 11:47 AM, Dan Williams wrote:
> On Thu, Jan 28, 2016 at 2:41 AM, Julian Margetson <runaway at candw.ms> wrote:
>> On 1/27/2016 3:34 PM, Dan Williams wrote:
>>> On Wed, Jan 27, 2016 at 2:18 AM, Julian Margetson <runaway at candw.ms>
>>> wrote:
>>>> On 1/26/2016 9:43 PM, Dan Williams wrote:
>>>> diff --git a/mm/memory.c b/mm/memory.c
>>>> index 30991f83d0bf..c44e387130b2 100644
>>>> --- a/mm/memory.c
>>>> +++ b/mm/memory.c
>>>> @@ -1521,6 +1521,8 @@ static int insert_pfn(struct vm_area_struct
>>>> *vma, unsigned long addr,
>>>>                  entry = pte_mkdevmap(pfn_t_pte(pfn, prot));
>>>>          else
>>>>                  entry = pte_mkspecial(pfn_t_pte(pfn, prot));
>>>> +       pr_info("%s: entry: %#llx pfn: %#lx\n", __func__,
>>>> +                       (unsigned long long) entry, pfn_t_to_pfn(pfn));
>>>>          set_pte_at(mm, addr, pte, entry);
>>>>          update_mmu_cache(vma, addr, pte); /* XXX: why not for
>>>> insert_page? */
>>>>
>>>> ...of course for the passing case you'll need to drop the call to
>>>> pfn_t_to_pfn() and just print the pfn directly.
>>>>
>>>> Thank you for the help tracking this down, it's much appreciated.
>>>>
>>>> Happy to help out. Just need some guidance sometimes as I am relatively
>>>> new
>>>> at this.
>>> No worries.
>>>
>>> So, below is the failing case, what does insert_pfn print in the
>>> passing case?  No need for the full log just the first few lines after
>>> starting X when running the commit before this failing one... (commit
>>> 69660fd797c3 "x86, mm: introduce _PAGE_DEVMAP").
>>>
>>> I'm still stumped given that PTE_RPN_SHIFT==PAGE_SHIFT in this
>>> configuration, so there's no 64-bit to 32-bit truncation to worry
>>> about...
>> Having a problem building .
>>
>>    CALL    scripts/checksyscalls.sh
>> <stdin>:1307:2: warning: #warning syscall copy_file_range not implemented
>> [-Wcpp]
>>    CHK     include/generated/compile.h
>>    CALL    arch/powerpc/kernel/systbl_chk.sh
>>    CC      mm/memory.o
>>    CHK     kernel/config_data.h
>> mm/memory.c: In function ‘insert_pfn’:
>> mm/memory.c:1520:9: error: implicit declaration of function
>> ‘pfn_t_to_pfn’ [-Werror=implicit-function-declaration]
>>           pr_info("%s: entry: %#llx pfn: %#lx\n", __func__,
>>           ^
>> mm/memory.c:1520:9: warning: format ‘%lx’ expects argument of type
>> ‘long unsigned int’, but argument 4 has type ‘int’ [-Wformat=]
> Yes, when you go to the preceding commit pfn_t_to_pfn() no longer
> exists.  You'll need to change the debug statement to:
>
> pr_info("%s: entry: %#llx pfn: %#lx\n", __func__,
>                         (unsigned long long) entry, pfn);
>
>
Thank you .
Not getting any debug output .

============================================================================================
         /* Ok, finally just insert the thing.. */
         entry = pte_mkspecial(pfn_pte(pfn, prot));
         pr_info("%s: entry: %#llx pfn: %#lx\n", __func__,
                       (unsigned long long) entry, pfn);
         set_pte_at(mm, addr, pte, entry);
         update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */

=============================================================================================

[   15.622581] systemd[1]: Mounted POSIX Message Queue File System.
[   15.785050] systemd[1]: Mounting Configuration File System...
[   15.888907] systemd[1]: Starting Apply Kernel Variables...
[   15.994762] systemd[1]: Mounting FUSE Control File System...
[   16.153688] systemd[1]: Mounted FUSE Control File System.

Ubuntu Xenial Xerus (development branch) Sam460ex ttyS0

Sam460ex login:




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