LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Eryu Guan <guan@eryu.me>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: fstests@vger.kernel.org, hare@suse.de, dgilbert@interlog.com,
	jeyu@kernel.org, lucas.demarchi@intel.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/3] common/scsi_debug: use the patient module remover
Date: Sun, 15 Aug 2021 20:35:02 +0800	[thread overview]
Message-ID: <YRkJ9rkFPyYUy8p5@desktop> (raw)
In-Reply-To: <20210811154512.1813622-4-mcgrof@kernel.org>

On Wed, Aug 11, 2021 at 08:45:12AM -0700, Luis Chamberlain wrote:
> If you try to run tests such as generic/108 in a loop
> you'll eventually see a failure, but the failure can
> be a false positive and the test was just unable to remove
> the scsi_debug module.
> 
> We need to give some time for the refcnt to become 0. For
> instance for the test generic/108 the refcnt lingers between
> 2 and 1. It should be 0 when we're done but a bit of time
> seems to be required. The chance of us trying to run rmmod
> when the refcnt is 2 or 1 is low, about 1/30 times if you
> run the test in a loop on linux-next today.
> 
> Likewise, even when its 0 we just need a tiny breather before
> we can remove the module (sleep 10 suffices) but this is
> only required on older kernels. Otherwise removing the module
> will just fail.
> 
> Some of these races are documented on the korg#212337, and
> Doug Gilbert has posted at least one patch attempt to try
> to help with this [1]. The patch does not resolve all the
> issues though, it helps though.
> 
> [0] https://bugzilla.kernel.org/show_bug.cgi?id=212337
> [1] https://lkml.kernel.org/r/20210508230745.27923-1-dgilbert@interlog.com
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  common/scsi_debug | 6 ++++--

There're also some "modprobe -r" calls in common/module, should the be
replaced with _patient_rmmod as well?

>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/common/scsi_debug b/common/scsi_debug
> index e7988469..3c9cd820 100644
> --- a/common/scsi_debug
> +++ b/common/scsi_debug
> @@ -4,11 +4,13 @@
>  #
>  # Functions useful for tests on unique block devices
>  
> +. common/module
> +
>  _require_scsi_debug()
>  {
>  	# make sure we have the module and it's not already used
>  	modinfo scsi_debug 2>&1 > /dev/null || _notrun "scsi_debug module not found"
> -	lsmod | grep -wq scsi_debug && (rmmod scsi_debug || _notrun "scsi_debug module in use")
> +	lsmod | grep -wq scsi_debug && (_patient_rmmod scsi_debug || _notrun "scsi_debug module in use")

I don't think we should use _patient_rmmod here, if we set timeout to
forever and there's actually some other process using scsi_debug module,
we'll loop forever here. And a failure to remove scsi_debug only results
in _notrun, and won't cause false test failure.

>  	# make sure it has the features we need
>  	# logical/physical sectors plus unmap support all went in together
>  	modinfo scsi_debug | grep -wq sector_size || _notrun "scsi_debug too old"
> @@ -53,5 +55,5 @@ _put_scsi_debug_dev()
>  		$UDEV_SETTLE_PROG
>  		n=$((n-1))
>  	done

I think the above while loop could be removed as well?

Thanks,
Eryu

> -	rmmod scsi_debug || _fail "Could not remove scsi_debug module"
> +	_patient_rmmod scsi_debug || _fail "Could not remove scsi_debug module"
>  }
> -- 
> 2.30.2

  reply	other threads:[~2021-08-15 12:35 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 15:45 [PATCH v2 0/3] fstests: add " Luis Chamberlain
2021-08-11 15:45 ` [PATCH v2 1/3] fstests: use udevadm settle after pvremove Luis Chamberlain
2021-08-15 12:36   ` Eryu Guan
2021-08-11 15:45 ` [PATCH v2 2/3] common/module: add patient module rmmod support Luis Chamberlain
2021-08-15 12:29   ` Eryu Guan
2021-08-18 14:02     ` Luis Chamberlain
2021-08-19  2:26       ` Eryu Guan
2021-08-19 23:58         ` Luis Chamberlain
2021-08-11 15:45 ` [PATCH v2 3/3] common/scsi_debug: use the patient module remover Luis Chamberlain
2021-08-15 12:35   ` Eryu Guan [this message]
2021-08-20  0:33     ` Luis Chamberlain

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=YRkJ9rkFPyYUy8p5@desktop \
    --to=guan@eryu.me \
    --cc=dgilbert@interlog.com \
    --cc=fstests@vger.kernel.org \
    --cc=hare@suse.de \
    --cc=jeyu@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lucas.demarchi@intel.com \
    --cc=mcgrof@kernel.org \
    --subject='Re: [PATCH v2 3/3] common/scsi_debug: use the patient module remover' \
    /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

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).