Re: [PATCH v5 04/18] sparc32: mm: Reduce allocation size for PMD and PTE tables

[Will Deacon]

On Sat, May 16, 2020 at 05:07:50PM -0700, Guenter Roeck wrote:
> On Sat, May 16, 2020 at 05:00:50PM -0700, Guenter Roeck wrote:
> > On Mon, May 11, 2020 at 09:41:36PM +0100, Will Deacon wrote:
> > > Now that the page table allocator can free page table allocations
> > > smaller than PAGE_SIZE, reduce the size of the PMD and PTE allocations
> > > to avoid needlessly wasting memory.
> > > 
> > > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > > Signed-off-by: Will Deacon <will@xxxxxxxxxx>
> > 
> > Something in the sparc32 patches in linux-next causes all my sparc32 emulations
> > to crash. bisect points to this patch, but reverting it doesn't help, and neither
> > does reverting the rest of the series.
> > 
> Actually, turns out I see the same pattern (lots of scheduling while atomic
> followed by 'killing interrupt handler' in cryptomgr_test) with several
> powerpc boot tests.  I am currently bisecting those crashes. I'll report
> the results here as well as soon as I have it.

FWIW, I retested my sparc32 patches with PREEMPT=y and I don't see any
issues. However, linux-next is a different story, where I don't get very far
at all:

BUG: Bad page state in process swapper  pfn:005b4

If you're seeing this on powerpc too, I wonder if it's related to:

https://lore.kernel.org/r/20200514170327.31389-1-rppt@xxxxxxxxxx

since I think it just hit -next and the diffstat is all over the place. I've
added Mike to CC just in case.

Will