From: Greg KH <gregkh@linuxfoundation.org>
To: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org
Subject: Re: Revert commit 310ca162d77
Date: Wed, 20 Mar 2019 16:16:28 +0100 [thread overview]
Message-ID: <20190320151628.GA32063@kroah.com> (raw)
In-Reply-To: <20190320125806.GD9485@quack2.suse.cz>
On Wed, Mar 20, 2019 at 01:58:06PM +0100, Jan Kara wrote:
> Hello,
>
> commit 310ca162d77 "block/loop: Use global lock for ioctl() operation." has
> been pushed to multiple stable trees. This patch is a part of larger series
> that overhauls the locking inside loopback device upstream and for 4.4,
> 4.9, and 4.14 stable trees only this patch from the series is applied. Our
> testing now has shown [1] that the patch alone makes present deadlocks
> inside loopback driver more likely (the openqa test in our infrastructure
> didn't hit the deadlock before whereas with the new kernel it hits it
> reliably every time). So I would suggest we revert 310ca162d77 from 4.4,
> 4.9, and 4.14 kernels.
>
> Another option would be to backport other locking fixes for the loop
> device but honestly I don't think that's a stable material - never heard
> of real users hitting problems, only syzkaller could, and we are still
> fixing up some small glitches resulting from that rework...
>
> Honza
>
> [1] https://bugzilla.suse.com/show_bug.cgi?id=1129739
Note, I do not have access to that bug report :(
next prev parent reply other threads:[~2019-03-20 15:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 12:58 Revert commit 310ca162d77 Jan Kara
2019-03-20 15:12 ` Greg KH
2019-03-20 15:16 ` Greg KH
2019-03-21 10:41 ` Jan Kara
2019-03-20 15:16 ` Greg KH [this message]
2019-03-21 10:26 ` Jan Kara
2019-04-29 12:05 ` Salvatore Bonaccorso
2019-04-29 14:04 ` Greg KH
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=20190320151628.GA32063@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=axboe@kernel.dk \
--cc=jack@suse.cz \
--cc=linux-block@vger.kernel.org \
--cc=stable@vger.kernel.org \
/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).