Re: linux-next: Tree for Feb 13 (runtime failures and 'non-zero nr_pmds' messages)

[Stephen Rothwell]

Hi Guenter,

On Fri, 13 Feb 2015 10:54:28 -0800 Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> I see a number of runtime failures with this version.
> It affects alpha, mips64, ppc64, and x86_64.
> Symptom is always the same. There are lots of
> 
> BUG: non-zero nr_pmds on freeing mm: X (where X is 1..4)
> 
> messages in the log, and the affected VMs don't reboot.
> 
> I don't see the problem in curent mainline, nor in mmotm.
> Bisect points to "Merge branch 'akpm-current/current'",
> which isn't really helpful.
> 
> Not sure if this is a bad merge resolution, so just take this
> as a heads-up for now.

Yours is the second report overnight (see attached).  Almost certainly
a bad merge resolution on my part (its a bit hard when Andrew get part
of his patch set merged by Linus :-()

I will fix up the merge on Monday (unless Andrew gets more stuff merged
or updates mmotm for me).

Sorry about that.
-- 
Cheers,
Stephen Rothwell                    sfr@xxxxxxxxxxxxxxxx
> --- Begin Message ---
> 2015-02-13, 16:56:15 +1100, Stephen Rothwell wrote:
> > Hi all,
> > 
> > Please do not add any material destined for v3.21 to your linux-next
> > included trees until after v3.20-rc1 has been released.
> > 
> > Changes since 20150212:
>
> Hi Stephen,
>
> Your conflict resolution in
>
> 8fe7fba50596 "Merge branch 'akpm-current/current'"
>
> for mm/memory.c looks a bit off.  I get flooded with these messages:
>
>   BUG: non-zero nr_pmds on freeing mm: 4
>
> and fixed it with:
>
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 450e4952c5ef..802adda2b0b6 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3350,7 +3350,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
>  	smp_wmb(); /* See comment in __pte_alloc */
>  
>  	spin_lock(&mm->page_table_lock);
> -	mm_inc_nr_pmds(mm);
>  #ifndef __ARCH_HAS_4LEVEL_HACK
>  	if (!pud_present(*pud)) {
>  		mm_inc_nr_pmds(mm);
>
>
> references:
> http://www.spinics.net/lists/linux-mm/msg84294.html
> dc6c9a35b66b "mm: account pmd page tables to the process"
>
> [CC'ed Kirill A. Shutemov]
>
>
> Thanks
>
> -- 
> Sabrina
>
> --- End Message ---

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