Re: kmem_cache_alloc panic in 3.10+

From: dormando
Date: Thu Jan 30 2014 - 22:53:06 EST


> On Thu, Jan 30, 2014 at 6:16 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> > On Wed, 2014-01-29 at 23:05 -0800, dormando wrote:
> >
> >> We hit the routing code fairly hard. Any hints for what to look at or how
> >> to instrument it? Or if it's fixed already? It's a real pain to iterate
> >> since it takes ~30 days to crash, usually. Sometimes.
>
> sounds like adding mdelay() didn't help to crash it sooner. Then I don't
> see how my dst fix was causing it to crash more often. Something odd.
> fyi just to check it more thoroughly I've been running with mdelay()
> and config_slub_debug_on for a week without issues.

Sorry, I'm actually trying to deal with two separate crashes at once :/
One is this 3.10.15 one, and one was the regression in 3.10.23 - I haven't
had time to attempt the mdelay test yet. The two crashes have fairly
distinct traces.

For what it's worth though the machines I have with that one patch
reverted are still running fine.

> > I really wonder... it looks like a possible in SLUB. (might be already
> > fixed)
> >
> > Could you try using SLAB instead ?
>
> try config_slub_debug_on=y ? it should catch double free and other things.
>

Any slowdowns/issues with that?
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