Re: frequent lockups in 3.18rc4

From: Dave Jones
Date: Mon Nov 17 2014 - 21:39:44 EST

On Mon, Nov 17, 2014 at 06:21:08PM -0800, Linus Torvalds wrote:
> On Mon, Nov 17, 2014 at 6:09 PM, Dave Jones <davej@xxxxxxxxxx> wrote:
> >
> > After wasting countless hours rolling back to Fedora 20 and gcc 4.8.1,
> > I saw the exact same trace on 3.17, so now I don't know what to think.
> Uhhuh.
> Has anything else changed? New trinity tests? If it has happened in as
> little as ten minutes, and you don't recall having seen this until
> about a week ago, it does sound like something changed.

Looking at the trinity commits over the last month or so, there's a few
new things, but nothing that sounds like it would trip up a bug like
this. "generate random ascii strings" and "mess with fcntl's after
opening fd's on startup" being the stand-outs. Everything else is pretty
much cleanups and code-motion. There was a lot of work on the code
that tracks mmaps about a month ago, but that shouldn't have had any
visible runtime differences.

<runs git diff>

hm, something I changed not that long ago, which I didn't commit yet,
was that it now runs more child processes than it used to (was 64, now 256)
I've been running like that for a while though. I want to say that was
before .17, but I'm not 100% sure.

So it could be that I'm just generating a lot more load now.
I could drop that back down and see if it 'goes away' or at least
happens less, but it strikes me that there's something here that needs
fixing regardless.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at