From: Luis Chamberlain <mcgrof@kernel.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: minchan@kernel.org, jeyu@kernel.org, ngupta@vflare.org,
sergey.senozhatsky.work@gmail.com, axboe@kernel.dk,
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 v3 1/3] zram: fix crashes due to use of cpu hotplug multistate
Date: Tue, 22 Jun 2021 08:12:10 -0700 [thread overview]
Message-ID: <20210622151210.lpbgnarxsbaakzdy@garbanzo> (raw)
In-Reply-To: <YNGTvN2cVOPr+duH@kroah.com>
On Tue, Jun 22, 2021 at 09:39:40AM +0200, Greg KH wrote:
> On Mon, Jun 21, 2021 at 04:30:11PM -0700, Luis Chamberlain wrote:
> > CPU 1 CPU 2
> >
> > class_unregister(...);
>
> Now the sysfs files are removed and invalidated for all devices
> associated with that class.
You're right the disksize_store() would have to happen before.
> > idr_for_each(...);
> > zram_debugfs_destroy();
> > disksize_store(...);
>
> How will this call into the kobject's store function if
> class_unregister() has already happened?
The disksize_store() would indeed have to happen before.
> > idr_destroy(...);
> > unregister_blkdev(...);
>
> Ah, it's a block device's store function you are worried about, not the
> class one?
In this case its about any files which can change the cpu compression
streams.
> > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > index cf8deecc39ef..431b60cd85c1 100644
> > --- a/drivers/block/zram/zram_drv.c
> > +++ b/drivers/block/zram/zram_drv.c
> > @@ -44,6 +44,8 @@ static DEFINE_MUTEX(zram_index_mutex);
> > static int zram_major;
> > static const char *default_compressor = CONFIG_ZRAM_DEF_COMP;
> >
> > +bool zram_up;
>
> static?
Will fix.
> > +
> > /* Module params (documentation at end) */
> > static unsigned int num_devices = 1;
> > /*
> > @@ -1704,6 +1706,7 @@ static void zram_reset_device(struct zram *zram)
> > comp = zram->comp;
> > disksize = zram->disksize;
> > zram->disksize = 0;
> > + zram->comp = NULL;
>
> Is this a new change?
It is a sanity change, but indeed, it is separate. I'll let Minchan
decide if he would prefer this to go out as a separate change.
Luis
next prev parent reply other threads:[~2021-06-22 15:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 23:30 [PATCH v3 0/3] zram: fix few sysfs races Luis Chamberlain
2021-06-21 23:30 ` [PATCH v3 1/3] zram: fix crashes due to use of cpu hotplug multistate Luis Chamberlain
2021-06-22 7:39 ` Greg KH
2021-06-22 15:12 ` Luis Chamberlain [this message]
2021-06-21 23:36 ` [PATCH v3 2/3] zram: fix deadlock with sysfs attribute usage and driver removal Luis Chamberlain
2021-06-22 7:41 ` Greg KH
2021-06-22 15:27 ` Luis Chamberlain
2021-06-22 16:27 ` Greg KH
2021-06-22 16:40 ` Luis Chamberlain
2021-06-22 16:51 ` Greg KH
2021-06-22 17:00 ` Luis Chamberlain
2021-06-22 7:45 ` Greg KH
2021-06-22 16:32 ` Luis Chamberlain
2021-06-22 17:16 ` Greg KH
2021-06-22 17:27 ` Luis Chamberlain
2021-06-22 18:05 ` Greg KH
2021-06-22 19:57 ` Luis Chamberlain
2021-06-21 23:36 ` [PATCH v3 3/3] drivers/base/core: refcount kobject and bus on device attribute read / store Luis Chamberlain
2021-06-22 7:46 ` Greg KH
2021-06-22 16:44 ` Luis Chamberlain
2021-06-22 16:48 ` Greg KH
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=20210622151210.lpbgnarxsbaakzdy@garbanzo \
--to=mcgrof@kernel.org \
--cc=axboe@kernel.dk \
--cc=gregkh@linuxfoundation.org \
--cc=jeyu@kernel.org \
--cc=jikos@kernel.org \
--cc=jpoimboe@redhat.com \
--cc=keescook@chromium.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mbenes@suse.com \
--cc=minchan@kernel.org \
--cc=ngupta@vflare.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky.work@gmail.com \
--cc=tglx@linutronix.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).