From: Greg KH <greg@kroah.com>
To: Andrew Patterson <andrew.patterson@hp.com>
Cc: Tejun Heo <teheo@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-hotplug@vger.kernel.org
Subject: Re: Error returns not handled correctly by sysfs.c:subsys_attr_store()
Date: Wed, 28 Nov 2007 12:05:53 -0800 [thread overview]
Message-ID: <20071128200553.GB22111@kroah.com> (raw)
In-Reply-To: <1196278300.5431.9.camel@grinch>
On Wed, Nov 28, 2007 at 12:31:40PM -0700, Andrew Patterson wrote:
> On Wed, 2007-11-28 at 16:42 +0900, Tejun Heo wrote:
> > Greg KH wrote:
> > > On Mon, Nov 26, 2007 at 08:31:16PM -0800, Andrew Morton wrote:
> > >> On Wed, 21 Nov 2007 15:16:59 -0700 Andrew Patterson <andrew.patterson@hp.com> wrote:
> > >>
> > >>> The buf in fs/sysfs.c:subsys_attr_store() does not seem to be updated
> > >>> correctly when returning a negative value (indicating that an error
> > >>> condition has occurred) is returned. If a negative value is returned,
> > >>> the next subsequent call to subsys_attr_store will have the contents of
> > >>> buf appended to the previous call.
> > >> subsys_attr_store() gets deleted by
> > >> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/gregkh-01-driver/kset-kill-subsys-attr.patch
> > >>
> > >> So maybe we will soon accidentally fix whatever-this-is? Or maybe we will
> > >> faithfully maintain it.
> > >
> > > Yes, subsys attributes go away, but this is showing a bug in the sysfs
> > > core with attributes, not in the "middle" layers of attributes.
> > >
> > > I bounced the original bug report to Tejun, who has been changing the
> > > logic around this area to see if he sees anything that might be
> > > different now.
> > >
> > > Tejun?
> >
> > Weird, the problem is not reproducible here.
> >
> > # echo a > allow_restart
> > -bash: echo: write error: Invalid argument
> > [ 437.518024] buf_ptr = 0xffff810005e20000, buf = x
> > [ 437.518027] , count = 2
> > # echo b > allow_restart
> > -bash: echo: write error: Invalid argument
> > [ 438.972973] buf_ptr = 0xffff81001be6f000, buf = y
> > [ 438.972976] , count = 2
> > # echo c > allow_restart
> > -bash: echo: write error: Invalid argument
> > [ 440.539747] buf_ptr = 0xffff81001d4ba000, buf = z
> > [ 440.539750] , count = 2
> >
> > Which is expected. On each open, sysfs_buffer is allocated with kzalloc
> > and the buffer is freed on close, so I don't see how it can happen.
> > Behavior for multiple write can be considered peculiar in that ppos is
> > essentially ignored and each write is passed just like brand new write
> > to ->store method but this too is the expected behavior.
> >
> > # (echo a; echo b; echo c) > allow_restart
> > [ 765.257132] buf_ptr = 0xffff81001be4f000, buf = a
> > [ 765.257135] , count = 2
> > [ 765.285474] buf_ptr = 0xffff81001be4f000, buf = b
> > [ 765.285484] , count = 2
> > [ 765.314002] buf_ptr = 0xffff81001be4f000, buf = c
> > [ 765.314004] , count = 2
> > -bash: echo: write error: Invalid argument
> > -bash: echo: write error: Invalid argument
> > -bash: echo: write error: Invalid argument
> >
> > Andrew Petterson, can you please build 2.6.24-rc3 from clean source tree
> > and retry?
> >
>
> I tried with clean 2.6.24-rc3 and get the same bad behavior. This is on
> an ia64 box, so maybe that is an issue. I can try on an x86 box as well.
Please do so.
> Oh, one other thing. I tried a "uname -r" to make sure I had the
> correct kernel booted and got:
>
> # uname -r
> 2.6.24-rc3
> x
> y
> z
Heh, that's not good, try a clean tree :)
thanks,
greg k-h
next prev parent reply other threads:[~2007-11-28 20:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-21 22:16 Error returns not handled correctly by sysfs.c:subsys_attr_store() Andrew Patterson
2007-11-27 4:31 ` Andrew Morton
2007-11-27 5:33 ` Greg KH
2007-11-27 5:38 ` Tejun Heo
2007-11-28 7:42 ` Tejun Heo
2007-11-28 19:31 ` Andrew Patterson
2007-11-28 20:05 ` Greg KH [this message]
2007-11-29 1:07 ` Tejun Heo
2007-12-03 21:15 ` Andrew Patterson
2007-12-21 20:35 ` Greg KH
2008-01-03 23:51 ` Andrew Patterson
2008-01-04 0:07 ` Tejun Heo
2008-01-04 0:17 ` Andrew Patterson
2008-01-04 0:56 ` Andrew Patterson
2008-01-04 7:30 ` Andrey Borzenkov
2008-01-07 21:13 ` Andrew Patterson
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=20071128200553.GB22111@kroah.com \
--to=greg@kroah.com \
--cc=akpm@linux-foundation.org \
--cc=andrew.patterson@hp.com \
--cc=linux-hotplug@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=teheo@suse.de \
/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).