From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Cyril Hrubis <chrubis@suse.cz>,
kernel test robot <rong.a.chen@intel.com>, LKP <lkp@01.org>,
LKML <linux-kernel@vger.kernel.org>,
ltp@lists.linux.it
Subject: Re: [LTP] 56cbb429d9: ltp.fs_fill.fail
Date: Fri, 26 Jul 2019 01:00:32 +0100 [thread overview]
Message-ID: <20190726000032.GK1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190725180428.GH1131@ZenIV.linux.org.uk>
On Thu, Jul 25, 2019 at 07:04:28PM +0100, Al Viro wrote:
> On Thu, Jul 25, 2019 at 09:32:13AM -0700, Linus Torvalds wrote:
> > On Thu, Jul 25, 2019 at 6:26 AM Cyril Hrubis <chrubis@suse.cz> wrote:
> > >
> > > This looks like mkfs.vfat got EBUSY after the loop device was
> > > succesfully umounted.
> >
> > Hmm. Smells like the RCU-delaying got triggered again.
> >
> > We have that "synchronize_rcu_expedited()" in namespace_unlock(),
> > which is so that everything should be done by the time we return to
> > user space.
> >
> > Al, maybe that RCU synchronization should be after the mntput()s?
>
> There are several interesting issues in there, but synchronize_rcu()
> should be between zeroing ->mnt_ns and dropping the final refs.
> I'm digging through that crap right now; at least one bug is dealt
> with by #fixes, but there's more, unfortunately.
No, it's not synchronize_rcu(). It's a bug dealt with in vfs.git #fixes,
triggering the struct mount leak in mount_subtree(), which is used
by btrfs. Immediately prior to vfat in their list...
(oh, and AFAICS "more" in the above had been a mismerge in -next, so
it might really be all there is to it)
Folks, see if vfs.git #fixes solves that one.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: ltp@lists.linux.it
Subject: [LTP] 56cbb429d9: ltp.fs_fill.fail
Date: Fri, 26 Jul 2019 01:00:32 +0100 [thread overview]
Message-ID: <20190726000032.GK1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190725180428.GH1131@ZenIV.linux.org.uk>
On Thu, Jul 25, 2019 at 07:04:28PM +0100, Al Viro wrote:
> On Thu, Jul 25, 2019 at 09:32:13AM -0700, Linus Torvalds wrote:
> > On Thu, Jul 25, 2019 at 6:26 AM Cyril Hrubis <chrubis@suse.cz> wrote:
> > >
> > > This looks like mkfs.vfat got EBUSY after the loop device was
> > > succesfully umounted.
> >
> > Hmm. Smells like the RCU-delaying got triggered again.
> >
> > We have that "synchronize_rcu_expedited()" in namespace_unlock(),
> > which is so that everything should be done by the time we return to
> > user space.
> >
> > Al, maybe that RCU synchronization should be after the mntput()s?
>
> There are several interesting issues in there, but synchronize_rcu()
> should be between zeroing ->mnt_ns and dropping the final refs.
> I'm digging through that crap right now; at least one bug is dealt
> with by #fixes, but there's more, unfortunately.
No, it's not synchronize_rcu(). It's a bug dealt with in vfs.git #fixes,
triggering the struct mount leak in mount_subtree(), which is used
by btrfs. Immediately prior to vfat in their list...
(oh, and AFAICS "more" in the above had been a mismerge in -next, so
it might really be all there is to it)
Folks, see if vfs.git #fixes solves that one.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: lkp@lists.01.org
Subject: Re: [LTP] 56cbb429d9: ltp.fs_fill.fail
Date: Fri, 26 Jul 2019 01:00:32 +0100 [thread overview]
Message-ID: <20190726000032.GK1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190725180428.GH1131@ZenIV.linux.org.uk>
[-- Attachment #1: Type: text/plain, Size: 1241 bytes --]
On Thu, Jul 25, 2019 at 07:04:28PM +0100, Al Viro wrote:
> On Thu, Jul 25, 2019 at 09:32:13AM -0700, Linus Torvalds wrote:
> > On Thu, Jul 25, 2019 at 6:26 AM Cyril Hrubis <chrubis@suse.cz> wrote:
> > >
> > > This looks like mkfs.vfat got EBUSY after the loop device was
> > > succesfully umounted.
> >
> > Hmm. Smells like the RCU-delaying got triggered again.
> >
> > We have that "synchronize_rcu_expedited()" in namespace_unlock(),
> > which is so that everything should be done by the time we return to
> > user space.
> >
> > Al, maybe that RCU synchronization should be after the mntput()s?
>
> There are several interesting issues in there, but synchronize_rcu()
> should be between zeroing ->mnt_ns and dropping the final refs.
> I'm digging through that crap right now; at least one bug is dealt
> with by #fixes, but there's more, unfortunately.
No, it's not synchronize_rcu(). It's a bug dealt with in vfs.git #fixes,
triggering the struct mount leak in mount_subtree(), which is used
by btrfs. Immediately prior to vfat in their list...
(oh, and AFAICS "more" in the above had been a mismerge in -next, so
it might really be all there is to it)
Folks, see if vfs.git #fixes solves that one.
next prev parent reply other threads:[~2019-07-26 0:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 11:09 56cbb429d9: ltp.fs_fill.fail kernel test robot
2019-07-25 11:09 ` kernel test robot
2019-07-25 11:09 ` [LTP] " kernel test robot
2019-07-25 13:26 ` Cyril Hrubis
2019-07-25 13:26 ` Cyril Hrubis
2019-07-25 13:26 ` Cyril Hrubis
2019-07-25 16:32 ` Linus Torvalds
2019-07-25 16:32 ` Linus Torvalds
2019-07-25 16:32 ` Linus Torvalds
2019-07-25 18:04 ` Al Viro
2019-07-25 18:04 ` Al Viro
2019-07-25 18:04 ` Al Viro
2019-07-26 0:00 ` Al Viro [this message]
2019-07-26 0:00 ` Al Viro
2019-07-26 0:00 ` Al Viro
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=20190726000032.GK1131@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=chrubis@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@01.org \
--cc=ltp@lists.linux.it \
--cc=rong.a.chen@intel.com \
--cc=torvalds@linux-foundation.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.