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Subject: Re: Stable/10 panic: uma_zfree: Freeing to non free bucket index.
From: hiren panchasara <hiren@FreeBSD.org>
To: John Baldwin <jhb@freebsd.org>
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Cc: Jeff Roberson <jeff@freebsd.org>, freebsd-stable@freebsd.org
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On Fri, May 30, 2014 at 8:09 AM, John Baldwin <jhb@freebsd.org> wrote:
> On Thursday, May 29, 2014 7:12:02 pm hiren panchasara wrote:
>> We are at stable/10 r261579. On a Xeon E5-2670 with 64GB ram, we saw this
> panic:
>>
>> Unread portion of the kernel message buffer:
>> panic: uma_zfree: Freeing to non free bucket index.
>
> A double free?  When I was at Y! there was a fairly common fdrop panic due to
> the ref count underflowing on 7.  I suspect this is the same bug, just being
> caught differently.  I was never able to find the culprit of the double free.
> :(

Very possible. :-(

Anyways, I'll see if we hit this again. FWIW, I've not seen such fdrop
failure lately.

Thanks a lot for responding, John.

Cheers,
Hiren