linux-nvme.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: sagi@grimberg.me (Sagi Grimberg)
Subject: nvmet: race condition while CQE are getting processed concurrently with the DISCONNECTED event
Date: Mon, 13 Mar 2017 10:05:53 +0200	[thread overview]
Message-ID: <ca954cbb-19a9-b061-982f-6ac98d4546fc@grimberg.me> (raw)
In-Reply-To: <33bffca1-f632-e2b2-3377-32fce207ac07@redhat.com>

> Hi Sagi

Hi Yi,

> With this patch, issue[1] cannot be reproduced, but I still can
> reproduce issue[2]. thanks
>
> [1]
>
> kernel NULL pointer on nvmet with stress
> rescan_controller/reset_controller test during I/O
>
> [2]
> mlx4_core 0000:07:00.0: swiotlb buffer is full and OOM observed during
> stress test on reset_controller

So this particular issue seems to do with the fact that the target is
attacked with reset attempts. The controller teardown happens
asynchronously and waits for safe termination while re-establishments
are allowed immediately.

I think we need to somehow figure out what is our max allowed active
controllers and simply refuse controller establishment if we exceeded
this number. The tricky part is to understand what this magic number
is?

Question, does the test in [2] complete eventually? or is this a fatal
error?

  reply	other threads:[~2017-03-13  8:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CY1PR12MB07747089AFFCB6115BBCF5ECBC210@CY1PR12MB0774.namprd12.prod.outlook.com>
2017-03-09 11:45 ` nvmet: race condition while CQE are getting processed concurrently with the DISCONNECTED event Sagi Grimberg
2017-03-11  8:29   ` Raju  Rangoju
2017-03-13  2:22   ` Yi Zhang
2017-03-13  8:05     ` Sagi Grimberg [this message]
2017-03-14 13:22       ` Yi Zhang
     [not found] <CY1PR12MB077418C35F6EA2499CBACA45BC2C0@CY1PR12MB0774.namprd12.prod.outlook.com>
2017-03-07 13:33 ` Sagi Grimberg
2017-03-08 15:46   ` Christoph Hellwig
2017-03-08 19:34     ` Sagi Grimberg

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ca954cbb-19a9-b061-982f-6ac98d4546fc@grimberg.me \
    --to=sagi@grimberg.me \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).