panic: detach with active requests on 10.1-RC3

[Guido Falsi]

On 10/26/14 16:30, Steven Hartland wrote:
> 
> On 26/10/2014 09:54, Guido Falsi wrote:
>> On 10/25/14 18:02, Guido Falsi wrote:
>>> On 10/25/14 17:02, Guido Falsi wrote:
>>>> On 10/24/14 15:26, Guido Falsi wrote:
>>>>> Hi,
>>>>>
>>>>> I'm making some experiments with 10.1-RC3 on alix boards as hardware
>>>>> using NanoBSD.
>>>>>
>>>>> By mounting and umounting UFS filesystems I have seen umount
>>>>> constantly
>>>>> hanging hard in a deadlock. I have tested on two boards with two
>>>>> distinct compactflash disks with same results. This was not happening
>>>>> with 10.0-RELEASE.
>>>>>
>>>>> I have build a 10.1-RC3 kernel with full debugging and caused the
>>>>> problem to happen, I got this:
>>>>>
>>>>> root at qtest:~ [0]# umount /cfg
>>>>> panic: detach with active requests
>>>>> KDB: stack backtrace:
>> [...]
>>> I must admit I am out of ideas.
>>>
>> I bisected commits and finally found out this happens starting with
>> r268815, which MFCed r268205.
>>
>> It is related to trim support, in fact disabling trim on the filesystm
>> "fixes" it.
>>
>> I filed bug #194606 on bugzilla [1] to further track this issue, if
>> anyone is interested.
>>
>> [1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=194606
> Nice work Guido, can you try the attached patch and see if that fixes it
> please?

It dies the same way with this patch applied. I tested applying the
patch both in stable/10 at r268815 and to a fresh releng/10.1.

-- 
Guido Falsi <madpilot at FreeBSD.org>