On Mon, 18 Oct 2010, Andrew Morton wrote:

On Mon, 18 Oct 2010 12:33:31 +0100
Mel Gorman [off-list ref] wrote:

quoted

A bit but I still don't know why it would cause corruption. Maybe this is still
a caching issue but the difference in timing between list_add and list_add_tail
is enough to hide the bug. It's also possible there are some registers
ioremapped after the memmap array and reading them is causing some
problem.

Andrew, what is the right thing to do here? We could flail around looking
for explanations as to why the bug causes a user buffer corruption but never
get an answer or do we go with this patch, preferably before 2.6.36 releases?

Well, you've spotted a bug so I'd say we fix it asap.

It's a bit of a shame that we lose the only known way of reproducing a
different bug, but presumably that will come back and bite someone else
one day, and we'll fix it then :(

I might be completely one off as usual, but this thing reminds me of a
bug I stared at yesterday night:

    http://permalink.gmane.org/gmane.linux.kernel/1049605

Reporter Cc'ed

Thanks,

	tglx