From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Angelo Compagnucci <angelo.compagnucci@gmail.com>,
Julia Lawall <julia.lawall@inria.fr>, <linux-iio@vger.kernel.org>
Subject: Re: [iio:fixes-togreg 19/19] drivers/iio/adc/mcp3422.c:147:3-9: preceding lock on line 137 (fwd)
Date: Tue, 1 Sep 2020 11:05:12 +0100 [thread overview]
Message-ID: <20200901110512.00003e52@Huawei.com> (raw)
In-Reply-To: <20200901090859.GA148841@kroah.com>
On Tue, 1 Sep 2020 11:08:59 +0200
Greg KH <gregkh@linuxfoundation.org> wrote:
> On Tue, Sep 01, 2020 at 09:50:41AM +0100, Jonathan Cameron wrote:
> > On Mon, 31 Aug 2020 11:09:53 +0200
> > Angelo Compagnucci <angelo.compagnucci@gmail.com> wrote:
> >
> > > Il giorno lun 31 ago 2020 alle ore 09:48 Julia Lawall
> > > <julia.lawall@inria.fr> ha scritto:
> > > >
> > > >
> > > >
> > > > On Mon, 31 Aug 2020, Angelo Compagnucci wrote:
> > > >
> > > > > Hi Julia,
> > > > >
> > > > > Il giorno sab 29 ago 2020 alle ore 22:29 Julia Lawall
> > > > > <julia.lawall@inria.fr> ha scritto:
> > > > > >
> > > > > > Please check whether there should be a mutex_unlock before line 147.
> > > > >
> > > > > Having a mutex_unlock before line 147 is wrong here, cause the lock
> > > > > should be held for the entire reading operation. Adding an unlock
> > > > > before the lock means that a concurrent call can unlock the lock
> > > > > previously held by another call and the result ends up mixing the
> > > > > reading for the first call to the reading of the second call.
> > > >
> > > > OK, I don't know the calling context. But you have a function where the
> > > > lock is held on the failure path and is released on the success path,
> > > > which seems at least a little strange.
> > >
> > > I see.
> > >
> > > I have to respin!
> > >
> > > Thanks for your support!
> > Hi Julia, Angelo,
> >
> > Please can we cc linux-iio@vger.kernel.org for such reports.
> > The fix has headed upstream. So we need to chase it with a fix asap.
> >
> > Greg, would you prefer a following fix (please cc Greg directly) or
> > to revert the patch?
> >
> > 3f1093d83d71 ("iio: adc: mcp3422: fix locking scope")
> >
> > Sorry I missed this one. Was working on wrong computer to access
> > the account this went to.
>
> A patch is always easier for me to apply than a revert is.
Great. Angelo replied very quickly so you should have it now
(thanks Angelo!)
Thanks for your help.
Jonathan
>
> thanks,
>
> greg k-h
prev parent reply other threads:[~2020-09-01 10:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.DEB.2.22.394.2008292228320.3629@hadrien>
[not found] ` <CA+TH9VkAo4CgCVDGvQumfePvNCg9ffwEHbqic7TsYJn4VZ3aTw@mail.gmail.com>
[not found] ` <alpine.DEB.2.22.394.2008310947020.2533@hadrien>
[not found] ` <CA+TH9VmQq3=Kf=f72CSn2ZziKP3YP6qjsXQL1nXzS-O8FscBWw@mail.gmail.com>
2020-09-01 8:50 ` [iio:fixes-togreg 19/19] drivers/iio/adc/mcp3422.c:147:3-9: preceding lock on line 137 (fwd) Jonathan Cameron
2020-09-01 9:08 ` Greg KH
2020-09-01 10:05 ` Jonathan Cameron [this message]
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