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From: Greg KH <gregkh@linuxfoundation.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
	minchan@kernel.org, jeyu@kernel.org, ngupta@vflare.org,
	sergey.senozhatsky.work@gmail.com, rafael@kernel.org,
	axboe@kernel.dk, tj@kernel.org, mbenes@suse.com,
	jpoimboe@redhat.com, tglx@linutronix.de, keescook@chromium.org,
	jikos@kernel.org, rostedt@goodmis.org, peterz@infradead.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 2/3] zram: fix deadlock with sysfs attribute usage and module removal
Date: Sun, 11 Jul 2021 07:00:42 +0200	[thread overview]
Message-ID: <YOp6+vlBRM5RqofW@kroah.com> (raw)
In-Reply-To: <20210710122851.aae9783ae9b1a703d565cbec@linux-foundation.org>

On Sat, Jul 10, 2021 at 12:28:51PM -0700, Andrew Morton wrote:
> On Fri,  2 Jul 2021 17:19:57 -0700 Luis Chamberlain <mcgrof@kernel.org> wrote:
> 
> > +#define MODULE_DEVICE_ATTR_FUNC_STORE(_name) \
> > +static ssize_t module_ ## _name ## _store(struct device *dev, \
> > +				   struct device_attribute *attr, \
> > +				   const char *buf, size_t len) \
> > +{ \
> > +	ssize_t __ret; \
> > +	if (!try_module_get(THIS_MODULE)) \
> > +		return -ENODEV; \
> > +	__ret = _name ## _store(dev, attr, buf, len); \
> > +	module_put(THIS_MODULE); \
> > +	return __ret; \
> > +}
> 
> I assume that Greg's comments on try_module_get() are applicable here
> also.

Yes, this is still broken code and does not do what it says it does,
please do not merge it.

Again, almost anything that does try_module_get(THIS_MODULE) is broken,
this code included.  I'll write more in a week or so when I get a chance
to get to this series in my reviews...

thanks,

greg k-h

  reply	other threads:[~2021-07-11  5:00 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-03  0:19 [PATCH v6 0/3] zram: fix few sysfs races Luis Chamberlain
2021-07-03  0:19 ` [PATCH v6 1/3] zram: fix crashes with cpu hotplug multistate Luis Chamberlain
2021-07-03  0:19 ` [PATCH v6 2/3] zram: fix deadlock with sysfs attribute usage and module removal Luis Chamberlain
2021-07-10 19:28   ` Andrew Morton
2021-07-11  5:00     ` Greg KH [this message]
2021-07-12 23:17     ` Luis Chamberlain
2021-07-21 11:29   ` Greg KH
2021-07-22 22:17     ` Luis Chamberlain
2021-07-23 11:15       ` Greg KH
2021-07-23 17:49         ` Luis Chamberlain
2021-07-27 17:35           ` Luis Chamberlain
2021-07-03  0:19 ` [PATCH v6 3/3] zram: use ATTRIBUTE_GROUPS Luis Chamberlain

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