On Sat, 15 Sep 2012, Jiri Slaby wrote:
> On 09/15/2012 02:00 AM, Michel Lespinasse wrote:
> > All right. Hugh managed to reproduce the issue on his suse laptop, and
> > I came up with a fix.
> >
> > The problem was that in mremap, the new vma's vm_{start,end,pgoff}
> > fields need to be updated before calling anon_vma_clone() so that the
> > new vma will be properly indexed.
> >
> > Patch attached. I expect this should also explain Jiri's reported
> > failure involving splitting THP pages during mremap(), even though we
> > did not manage to reproduce that one.
>
> Oh, great. This is BTW also machine with suse.
We guessed that for you it might be :)
I've not yet moved up from 11.4 by the way, if that makes a difference.
In fact, even before these reports, when Michel was wondering about the
uses of mremap, I did mention an mremap/THP bug from a year ago, which
the SuSE update had been good for reproducing.
> What was the way that
> Hugh used to reproduce the other issue?
I've lost track of which issue is "other".
To reproduce Sasha's interval_tree.c warnings, all I had to do was switch
on CONFIG_DEBUG_VM_RB (I regret not having done so before) and boot up.
I didn't look to see what was doing the mremap which caused the warning
until now: surprisingly, it's microcode_ctl. I've not made much effort
to get the right set of sources and work out why that would be using
mremap (a realloc inside a library?).
I failed to reproduce your BUG in huge_memory.c, but what I was trying
was SuSE update via yast2, on several machines; but perhaps because
they were all fairly close to up-to-date, I didn't hit a problem.
(That was before I turned on DEBUG_VM_RB for Sasha's.)
Hugh
> For me it happened twice in a
> row when using zypper to upgrade packages. But it did not happen any
> more after that.
>
> thanks,
> --
> js
> suse labs
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>