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"axboe@kernel.dk" Subject: Re: [PATCH] block: prevent sending events from removed device Thread-Topic: [PATCH] block: prevent sending events from removed device Thread-Index: AQHXbYcPaY+gyAaNCEO3EseEwW+vDqstvh0AgAALZm0= Date: Thu, 1 Jul 2021 08:23:39 +0000 Message-ID: References: , In-Reply-To: Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [185.80.168.10] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: b2605fd0-b342-405d-9850-08d93c6987a3 x-ms-traffictypediagnostic: CWXP265MB2951: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:2582 x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0 x-microsoft-antispam-message-info: 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=?iso-8859-1?Q?nfkPt4biIbKD8QmbaOG3bIXNJXJPeaZaO/+J6uoDtnx8uZbRkqaXEapJLK?= =?iso-8859-1?Q?R6VnqiQmKdoIjy+Glx7gzipJdMnsH8Cv9Q38FqvBKqnZl5zfJEQuca0kGu?= =?iso-8859-1?Q?zzEJdpi0koAZNk5VYQ/hq2v8KUWlotG3r/3TFoUji0qyeoyGlqesQeulp2?= =?iso-8859-1?Q?IVCJK+c77bmzbK+/Min1NhyxPqnIaJCEtmMymwALgAG3racHrLG0Jy3nJ5?= =?iso-8859-1?Q?p6Jjt39FYMUScvQxtEIQbfiIkzP8k19BlJBtobaztYot/GM=3D?= x-ms-exchange-transport-forked: True MIME-Version: 1.0 X-OriginatorOrg: hyperstone.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: CWXP265MB2680.GBRP265.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-Network-Message-Id: b2605fd0-b342-405d-9850-08d93c6987a3 X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Jul 2021 08:23:39.3100 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 86f203eb-e878-4188-b297-34c118c18b11 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: gS4roEZ/wLZ98r3m4qDQ1QN73ozF6N9nk0K6M5O2mJ5vbaMOeqe7YPy5HJ6DLj9Jl9uJ2m3eI265cSEpZWvaig== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CWXP265MB2951 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: hyperstone.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alright Thanks, I will try out your suggestion and report back. Regards, Christian >I don't see how this is going to work.  If the device is being >deleted the reference count will be zero and refcount_inc as >called from kobject_get will WARN.  We'll need to check the >disk is marked up, and we need to do that under a lock. > >Something like this completely untested patch: diff --git a/block/disk-events.c b/block/disk-events.c index a75931ff5da4..27b845c51f2a 100644 --- a/block/disk-events.c +++ b/block/disk-events.c @@ -190,6 +190,9 @@ static void disk_check_events(struct disk_events *ev,            spin_unlock_irq(&ev->lock);   +       if (!(disk->flags & GENHD_FL_UP)) +               return; +          /*           * Tell userland about new events.  Only the events listed in           * @disk->events are reported, and only if DISK_EVENT_FLAG_UEVENT @@ -268,6 +271,8 @@ bool bdev_check_media_change(struct block_device *bdev)  {          unsigned int events;   +       lockdep_assert_held(&bdev->bd_disk->open_mutex); +          events = disk_clear_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE |                                     DISK_EVENT_EJECT_REQUEST);          if (!(events & DISK_EVENT_MEDIA_CHANGE)) @@ -290,7 +295,10 @@ static void disk_events_workfn(struct work_struct *work)          struct delayed_work *dwork = to_delayed_work(work);          struct disk_events *ev = container_of(dwork, struct disk_events, dwork);   -       disk_check_events(ev, &ev->clearing); +       mutex_lock(&ev->disk->open_mutex); +       if (ev->disk->flags & GENHD_FL_UP) +               disk_check_events(ev, &ev->clearing); +       mutex_unlock(&ev->disk->open_mutex);  }    /* diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c index a093644ac39f..b8e77da44235 100644 --- a/drivers/block/ataflop.c +++ b/drivers/block/ataflop.c @@ -1735,8 +1735,10 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode,                  /* invalidate the buffer track to force a reread */                  BufferDrive = -1;                  set_bit(drive, &fake_change); +               mutex_lock(&bdev->bd_disk->open_mutex);                  if (bdev_check_media_change(bdev))                          floppy_revalidate(bdev->bd_disk); +               mutex_unlock(&bdev->bd_disk->open_mutex);                  return 0;          default:                  return -EINVAL; diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 87460e0e5c72..2a97f22cfa0b 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3185,8 +3185,10 @@ static int invalidate_drive(struct block_device *bdev)          /* invalidate the buffer track to force a reread */          set_bit((long)bdev->bd_disk->private_data, &fake_change);          process_fd_request(); +       mutex_lock(&bdev->bd_disk->open_mutex);          if (bdev_check_media_change(bdev))                  floppy_revalidate(bdev->bd_disk); +       mutex_unlock(&bdev->bd_disk->open_mutex);          return 0;  }   Hyperstone GmbH | Line-Eid-Strasse 3 | 78467 Konstanz Managing Directors: Dr. Jan Peter Berns. 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