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Date:   Mon, 22 Mar 2021 12:35:23 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        Randy Dunlap <rdunlap@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Joe Perches <joe@perches.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] devcoredump: avoid -Wempty-body warnings
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On Mon, Mar 22, 2021 at 12:22:11PM +0100, Arnd Bergmann wrote:
> On Mon, Mar 22, 2021 at 11:29 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Mon, Mar 22, 2021 at 11:19:53AM +0100, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <arnd@arndb.de>
> > > +      * These should normally not fail, but there is no problem
> > > +      * continuing without the links, so just warn instead of
> > > +      * failing.
> > > +      */
> > > +     WARN_ON_ONCE(sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj,
> > > +                                    "failing_device"));
> > >
> > > -     if (sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
> > > -                           "devcoredump"))
> > > -             /* nothing - symlink will be missing */;
> > > +     WARN_ON_ONCE(sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
> > > +                                    "devcoredump"));
> >
> > We do not want to reboot machines that have panic-on-warn set,
> 
> Fair enough.
> 
> > so if this really needs a trace dump, please do that instead...
> 
> I don't think the backtrace is needed here, if it ever happens it's either
> going to be -ENOMEM or completely reproducible. I can instead
> do the cast to (void) that Linus suggested, or a simple if(...) dev_warn()
> or dev_warn_once() to have some indication of the failure.

dev_warn() should be fine I think.

thanks,

greg k-h