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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
	Minchan Kim <minchan@kernel.org>,
	keescook@chromium.org, dhowells@redhat.com, hch@infradead.org,
	mbenes@suse.com, ngupta@vflare.org,
	sergey.senozhatsky.work@gmail.com, axboe@kernel.dk,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Jessica Yu <jeyu@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/2] zram: fix crashes due to use of cpu hotplug multistate
Date: Wed, 7 Apr 2021 15:17:46 -0500	[thread overview]
Message-ID: <20210407201746.ueijmegmpbyq5quv@treble> (raw)
In-Reply-To: <YGbNpLKXfWpy0ZZa@kroah.com>

On Fri, Apr 02, 2021 at 09:54:12AM +0200, Greg KH wrote:
> On Thu, Apr 01, 2021 at 11:59:25PM +0000, Luis Chamberlain wrote:
> > As for the syfs deadlock possible with drivers, this fixes it in a generic way:
> > 
> > commit fac43d8025727a74f80a183cc5eb74ed902a5d14
> > Author: Luis Chamberlain <mcgrof@kernel.org>
> > Date:   Sat Mar 27 14:58:15 2021 +0000
> > 
> >     sysfs: add optional module_owner to attribute
> >     
> >     This is needed as otherwise the owner of the attribute
> >     or group read/store might have a shared lock used on driver removal,
> >     and deadlock if we race with driver removal.
> >     
> >     Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> 
> No, please no.  Module removal is a "best effort", if the system dies
> when it happens, that's on you.  I am not willing to expend extra energy
> and maintance of core things like sysfs for stuff like this that does
> not matter in any system other than a developer's box.

So I mentioned this on IRC, and some folks were surprised to hear that
module unloading is unsupported and is just a development aid.

Is this stance documented anywhere?

If we really believe this to be true, we should make rmmod taint the
kernel.

-- 
Josh


  parent reply	other threads:[~2021-04-07 20:18 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-06  2:20 [PATCH 0/2] zram: fix few ltp zram02.sh crashes Luis Chamberlain
2021-03-06  2:20 ` [PATCH 1/2] zram: fix crashes due to use of cpu hotplug multistate Luis Chamberlain
2021-03-09  2:55   ` Minchan Kim
2021-03-10 13:11     ` Luis Chamberlain
2021-03-10 21:25       ` Luis Chamberlain
2021-03-12  2:08       ` Minchan Kim
2021-03-10 21:21     ` Luis Chamberlain
2021-03-12  2:14       ` Minchan Kim
2021-03-12 18:32         ` Luis Chamberlain
2021-03-12 19:28           ` Minchan Kim
2021-03-19 19:09             ` Luis Chamberlain
2021-03-22 16:37               ` Minchan Kim
2021-03-22 20:41                 ` Luis Chamberlain
2021-03-22 22:12                   ` Minchan Kim
2021-04-01 23:59                     ` Luis Chamberlain
2021-04-02  7:54                       ` Greg KH
2021-04-02 18:30                         ` Luis Chamberlain
2021-04-03  6:13                           ` Greg KH
     [not found]                             ` <20210406003152.GZ4332@42.do-not-panic.com>
2021-04-06 12:00                               ` Miroslav Benes
2021-04-06 15:54                                 ` Josh Poimboeuf
2021-04-07 14:09                                   ` Peter Zijlstra
2021-04-07 15:30                                     ` Josh Poimboeuf
2021-04-07 16:48                                       ` Peter Zijlstra
2021-04-07 20:17                         ` Josh Poimboeuf [this message]
2021-04-08  6:18                           ` Greg KH
2021-04-08 13:16                             ` Steven Rostedt
2021-04-08 13:37                             ` Josh Poimboeuf
2021-04-08  1:37                         ` Thomas Gleixner
2021-04-08  6:16                           ` Greg KH
2021-04-08  8:01                             ` Jiri Kosina
2021-04-08  8:09                               ` Greg KH
2021-04-08  8:35                                 ` Jiri Kosina
2021-04-08  8:55                                   ` Greg KH
2021-04-08 18:40                                     ` Luis Chamberlain
2021-04-09  3:01                                     ` Kees Cook
2021-04-05 17:07                       ` Minchan Kim
2021-04-05 19:00                         ` Luis Chamberlain
2021-04-05 19:58                           ` Minchan Kim
2021-04-06  0:29                             ` Luis Chamberlain
2021-04-07  1:23                               ` Minchan Kim
2021-04-07  1:38                                 ` Minchan Kim
2021-04-07 14:52                                   ` Luis Chamberlain
2021-04-07 14:50                                 ` Luis Chamberlain
2021-03-06  2:20 ` [PATCH 2/2] zram: fix races of sysfs attribute removal and usage Luis Chamberlain

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