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Subject: Re: mlx4en, timer irq @100%... (11.0 stuck on high network load ???)
To: Slawa Olhovchenkov <slw@zxy.spb.ru>
Cc: jch <jch@FreeBSD.org>, FreeBSD Net <freebsd-net@freebsd.org>,
 FreeBSD Stable <freebsd-stable@freebsd.org>,
 Ben RUBSON <ben.rubson@gmail.com>, hiren <hiren@strugglingcoder.info>
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From: Hans Petter Selasky <hps@selasky.org>
Message-ID: <da31fd4d-9226-f2e4-0d5e-b8c05ee66f10@selasky.org>
Date: Tue, 8 Aug 2017 13:59:08 +0200
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On 08/08/17 13:56, Slawa Olhovchenkov wrote:
> On Tue, Aug 08, 2017 at 01:49:08PM +0200, Hans Petter Selasky wrote:
> 
>> On 08/08/17 13:33, Slawa Olhovchenkov wrote:
>>> TW_RUNLOCK(V_tw_lock);
>>> and
>>> if (INP_INFO_TRY_WLOCK(&V_tcbinfo)) {
>>>
>>> `inp` can be invalidated, freed and this pointer may be invalid?
>>
>> If you look one line up there is a pcbref ??
> 
> Yes.
> Can different thread take this inp and freed it?
> May be timer thread?

No, it cannot be freed while there is a ref.

Some lines down the ref is dropped once the inp pointer is no longer needed.

--HPS