Re: [PATCH] mm,shmem: Fix a typo in shmem_swapin_page()

Matthew Wilcox [off-list ref] writes:

On Tue, Aug 03, 2021 at 04:14:38PM +0800, Huang, Ying wrote:

quoted

Matthew Wilcox [off-list ref] writes:

quoted

But I REALLY REALLY REALLY want a reproducer.  Right now, I have a hard
time believing this, or any of the other races can really happen.

I think the race is only theoretical too.  Firstly, swapoff is a rare
operations in practice; secondly, the race window is really small.

So do something to provoke it.  Widen the window.  Put an msleep(1000)
between *pagep = NULL and the call to get_swap_device().  That's assuming
that the swapon/swapoff loop that I proposed doesn't work.  Did you
try it?

I haven't tried it.  Do you agree that the race is possible in theory?
But if you still really want it, I can try to do that.

Best Regards,
Huang, Ying