From: Ming Lei <ming.lei@redhat.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
tj@kernel.org, gregkh@linuxfoundation.org,
akpm@linux-foundation.org, minchan@kernel.org, jeyu@kernel.org,
shuah@kernel.org, bvanassche@acm.org, dan.j.williams@intel.com,
joe@perches.com, tglx@linutronix.de, keescook@chromium.org,
rostedt@goodmis.org, linux-spdx@vger.kernel.org,
linux-doc@vger.kernel.org, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 11/12] zram: fix crashes with cpu hotplug multistate
Date: Wed, 20 Oct 2021 09:15:20 +0800 [thread overview]
Message-ID: <YW9tqPunx5bssxIz@T590> (raw)
In-Reply-To: <YW8eSq2B+5FtOLZb@bombadil.infradead.org>
On Tue, Oct 19, 2021 at 12:36:42PM -0700, Luis Chamberlain wrote:
> On Wed, Oct 20, 2021 at 12:29:53AM +0800, Ming Lei wrote:
> > On Tue, Oct 19, 2021 at 08:28:21AM -0700, Luis Chamberlain wrote:
> > > On Tue, Oct 19, 2021 at 10:34:41AM +0800, Ming Lei wrote:
> > > > Please try the following patch against upstream(linus or next) tree(basically
> > > > fold revised 2 and 3 of V1, and cover two issues: not fail zram_remove in
> > > > module_exit(), race between zram_remove() and disksize_store()), and see if
> > > > everything is fine for you:
> > >
> > > Page fault ...
> > >
> > > [ 18.284256] zram: Removed device: zram0
> > > [ 18.312974] BUG: unable to handle page fault for address:
> > > ffffad86de903008
> > > [ 18.313707] #PF: supervisor read access in kernel mode
> > > [ 18.314248] #PF: error_code(0x0000) - not-present page
> > > [ 18.314797] PGD 100000067 P4D 100000067 PUD 10031e067 PMD 136a28067
> >
> > That is another race between zram_reset_device() and disksize_store(),
> > which is supposed to be covered by ->init_lock, and follows the delta fix
> > against the last patch I posted, and the whole patch can be found in the
> > github link:
> >
> > https://github.com/ming1/linux/commit/fa6045b1371eb301f392ac84adaf3ad53bb16894
> >
> >
> > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > index d0cae7a42f4d..a14ba3d350ea 100644
> > --- a/drivers/block/zram/zram_drv.c
> > +++ b/drivers/block/zram/zram_drv.c
> > @@ -1704,12 +1704,12 @@ static void zram_reset_device(struct zram *zram)
> > set_capacity_and_notify(zram->disk, 0);
> > part_stat_set_all(zram->disk->part0, 0);
> >
> > - up_write(&zram->init_lock);
> > /* I/O operation under all of CPU are done so let's free */
> > zram_meta_free(zram, disksize);
> > memset(&zram->stats, 0, sizeof(zram->stats));
> > zcomp_destroy(comp);
> > reset_bdev(zram);
> > + up_write(&zram->init_lock);
> > }
> >
> > static ssize_t disksize_store(struct device *dev,
>
> With this, it still ends up in a state where we loop and can't get out of:
>
> zram: Can't change algorithm for initialized device
Again, you are running two zram02.sh[1] on /dev/zram0, that isn't unexpected
behavior. Here the difference is just timing. In my test VM,
this message shows a while on one task, then it may be switched to
another task.
Just run your patches a while, nothing real difference here, and the
following message can be dumped from one task for long time:
can't set '107374182400' to /sys/block/zram0/disksize
Also you did not answer my question about your test expected result when
running the following script from two terminal concurrently:
while true; do
PATH=$PATH:$PWD:$PWD/../../../lib/ ./zram02.sh;
done
Thanks,
Ming
next prev parent reply other threads:[~2021-10-20 1:16 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 16:37 [PATCH v8 00/12] syfs: generic deadlock fix with module removal Luis Chamberlain
2021-09-27 16:37 ` [PATCH v8 01/12] LICENSES: Add the copyleft-next-0.3.1 license Luis Chamberlain
[not found] ` <202110050907.35FBD2A1@keescook>
[not found] ` <YWR2ZrtzChamY1y4@bombadil.infradead.org>
2021-10-11 17:57 ` Kees Cook
2021-09-27 16:37 ` [PATCH v8 02/12] testing: use the copyleft-next-0.3.1 SPDX tag Luis Chamberlain
2021-10-05 16:11 ` Kees Cook
2021-09-27 16:37 ` [PATCH v8 03/12] selftests: add tests_sysfs module Luis Chamberlain
2021-10-05 14:16 ` Greg KH
2021-10-05 16:57 ` Tim.Bird
2021-10-11 17:40 ` Luis Chamberlain
2021-10-11 17:38 ` Luis Chamberlain
2021-10-07 14:23 ` Miroslav Benes
2021-10-11 19:11 ` Luis Chamberlain
[not found] ` <202110050912.3DF681ED@keescook>
2021-10-11 19:03 ` Luis Chamberlain
2021-09-27 16:37 ` [PATCH v8 04/12] kernfs: add initial failure injection support Luis Chamberlain
2021-10-05 19:47 ` Kees Cook
2021-10-11 20:44 ` Luis Chamberlain
2021-09-27 16:37 ` [PATCH v8 05/12] test_sysfs: add support to use kernfs failure injection Luis Chamberlain
2021-10-05 19:51 ` Kees Cook
2021-10-11 20:56 ` Luis Chamberlain
2021-09-27 16:37 ` [PATCH v8 06/12] kernel/module: add documentation for try_module_get() Luis Chamberlain
2021-10-05 19:58 ` Kees Cook
2021-10-11 21:16 ` Luis Chamberlain
2021-09-27 16:38 ` [PATCH v8 07/12] fs/kernfs/symlink.c: replace S_IRWXUGO with 0777 on kernfs_create_link() Luis Chamberlain
2021-10-05 19:59 ` Kees Cook
2021-09-27 16:38 ` [PATCH v8 08/12] fs/sysfs/dir.c: replace S_IRWXU|S_IRUGO|S_IXUGO with 0755 sysfs_create_dir_ns() Luis Chamberlain
2021-10-05 16:05 ` Kees Cook
2021-09-27 16:38 ` [PATCH v8 09/12] sysfs: fix deadlock race with module removal Luis Chamberlain
2021-10-05 9:24 ` Ming Lei
2021-10-11 21:25 ` Luis Chamberlain
2021-10-12 0:20 ` Ming Lei
2021-10-12 21:18 ` Luis Chamberlain
2021-10-13 1:07 ` Ming Lei
2021-10-13 12:35 ` Luis Chamberlain
2021-10-13 15:04 ` Ming Lei
2021-10-13 21:16 ` Luis Chamberlain
2021-10-05 20:50 ` Kees Cook
2021-10-11 22:26 ` Luis Chamberlain
2021-10-13 12:41 ` Luis Chamberlain
2021-09-27 16:38 ` [PATCH v8 10/12] test_sysfs: enable deadlock tests by default Luis Chamberlain
2021-09-27 16:38 ` [PATCH v8 11/12] zram: fix crashes with cpu hotplug multistate Luis Chamberlain
2021-10-05 20:55 ` Kees Cook
2021-10-11 18:27 ` Luis Chamberlain
2021-10-14 1:55 ` Ming Lei
2021-10-14 2:11 ` Ming Lei
2021-10-14 20:24 ` Luis Chamberlain
2021-10-14 23:52 ` Ming Lei
2021-10-15 0:22 ` Luis Chamberlain
2021-10-15 8:36 ` Ming Lei
2021-10-15 8:52 ` Greg KH
2021-10-15 17:31 ` Luis Chamberlain
2021-10-16 11:28 ` Ming Lei
2021-10-18 19:32 ` Luis Chamberlain
2021-10-19 2:34 ` Ming Lei
2021-10-19 6:23 ` Miroslav Benes
2021-10-19 9:23 ` Ming Lei
2021-10-20 6:43 ` Miroslav Benes
2021-10-20 7:49 ` Ming Lei
2021-10-20 8:19 ` Miroslav Benes
2021-10-20 8:28 ` Greg KH
2021-10-25 9:58 ` Miroslav Benes
2021-10-20 10:09 ` Ming Lei
2021-10-26 8:48 ` Petr Mladek
2021-10-26 15:37 ` Ming Lei
2021-10-26 17:01 ` Luis Chamberlain
2021-10-27 11:57 ` Miroslav Benes
2021-10-27 14:27 ` Luis Chamberlain
2021-11-02 15:24 ` Petr Mladek
2021-11-02 16:25 ` Luis Chamberlain
2021-11-03 0:01 ` Ming Lei
2021-11-03 12:44 ` Luis Chamberlain
2021-10-27 11:42 ` Miroslav Benes
2021-11-02 14:15 ` Petr Mladek
2021-11-02 14:51 ` Petr Mladek
2021-11-02 15:17 ` Ming Lei
2021-11-02 14:56 ` Ming Lei
2021-10-19 15:28 ` Luis Chamberlain
2021-10-19 16:29 ` Ming Lei
2021-10-19 19:36 ` Luis Chamberlain
2021-10-20 1:15 ` Ming Lei [this message]
2021-10-20 15:48 ` Luis Chamberlain
2021-10-21 0:39 ` Ming Lei
2021-10-21 17:18 ` Luis Chamberlain
2021-10-22 0:05 ` Ming Lei
2021-10-19 15:50 ` Luis Chamberlain
2021-10-19 16:25 ` Greg KH
2021-10-19 16:30 ` Luis Chamberlain
2021-10-19 17:28 ` Greg KH
2021-10-19 19:46 ` Luis Chamberlain
2021-10-19 16:39 ` Ming Lei
2021-10-19 19:38 ` Luis Chamberlain
2021-10-20 0:55 ` Ming Lei
2021-09-27 16:38 ` [PATCH v8 12/12] zram: use ATTRIBUTE_GROUPS to fix sysfs deadlock module removal Luis Chamberlain
2021-10-05 20:57 ` Kees Cook
2021-10-11 18:28 ` Luis Chamberlain
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