Messages in this thread | | | Date | Mon, 12 Sep 2005 16:43:19 +0200 | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: [PATCH] fix kernel oops, when IDE-Device (CF-Card) is removed while mounted. |
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On 9/6/05, Thomas Kleffel <tk@maintech.de> wrote: > Hello,
Hi,
> when I physically remove a CF-Card while it is still mounted and > accessed, the result is a kernel oops. I traced the problem down to the > following situation: > > 1) Physical device is removed and the corresponding ide_trive_t gets > deleted, reference to the contained *queue is given back and queue gets > deleted. > > 2) struct block_device still exists, because the device is still > mounted, and points to a struct gendisk, which contains the - now > invalid - pointer to the queue that was destructed earlier. > > 3) As soon as a request is sent to the block device, the queue pointer > is used and the kernel oopses. > > To fix this matter, I've made the following changes: > > 1a) When a queue is attached to a struct gendisk by ide_disk_probe(), > its reference counter shall be incremented by a blk_get_queue()-call. > > 1b) When a disk is released by disk_release(), its queue's reference > count shall be decremented by calling blk_cleanup_queue().
Which conflicts with IDE layer reference counting & locking scheme as IDE layer can send (special) requests to the device without any device driver loaded.
> 2a) When a physical drive is released by drive_release_dev(), the > corresponding queue is marked dead, so that no further calls to the > physical device's queue-handler are made. > > 2b) When a request is submitted to a dead queue using > generic_make_request(), the request shall be failed immedaiately with > -ENXIO which causes the caller to recive a "Bus error". This is the same > beaviour as when a USB-Storage device gets pulled while in use.
The fix would be to fail the previous requests during removal of the device [ somebody already posted a patch to do that but I didn't have time to give it proper thought ] or alternatively to add the offline state to the device [ so processing of the requests would be resumed after device is online again ].
Thanks, Bartlomiej
> diff -uprN -X b/Documentation/dontdiff a/drivers/block/genhd.c > b/drivers/block/genhd.c > --- a/drivers/block/genhd.c 2005-08-08 15:30:13.000000000 +0200 > +++ b/drivers/block/genhd.c 2005-09-05 02:07:46.000000000 +0200 > @@ -415,6 +415,9 @@ static struct attribute * default_attrs[ > static void disk_release(struct kobject * kobj) > { > struct gendisk *disk = to_disk(kobj); > + > + blk_cleanup_queue(disk->queue); > + > kfree(disk->random); > kfree(disk->part); > free_disk_stats(disk); > diff -uprN -X b/Documentation/dontdiff a/drivers/block/ll_rw_blk.c > b/drivers/block/ll_rw_blk.c > --- a/drivers/block/ll_rw_blk.c 2005-08-13 15:54:15.000000000 +0200 > +++ b/drivers/block/ll_rw_blk.c 2005-09-05 02:08:35.000000000 +0200 > @@ -2877,15 +2877,26 @@ end_io: > } > > if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) { > - printk("bio too big device %s (%u > %u)\n", > + printk(KERN_ERR > + "generic_make_request: " > + "bio too big device %s (%u > %u)\n", > bdevname(bio->bi_bdev, b), > bio_sectors(bio), > q->max_hw_sectors); > goto end_io; > } > > - if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) > - goto end_io; > + if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { > + printk(KERN_ERR > + "generic_make_request: access to " > + "dead device %s (%Lu)\n", > + bdevname(bio->bi_bdev, b), > + (long long) bio->bi_sector); > + bio_endio(bio, bio->bi_size, -ENXIO); > + break; > + } > > block_wait_queue_running(q); > > diff -uprN -X b/Documentation/dontdiff a/drivers/ide/ide-disk.c > b/drivers/ide/ide-disk.c > --- a/drivers/ide/ide-disk.c 2005-08-24 17:58:02.000000000 +0200 > +++ b/drivers/ide/ide-disk.c 2005-09-05 02:10:30.000000000 +0200 > @@ -1224,6 +1221,9 @@ static int ide_disk_probe(struct device > if (!g) > goto out_free_idkp; > > + if(0 != blk_get_queue(drive->queue)) > + goto out_free_idkp; > + > ide_init_disk(g, drive); > > ide_register_subdriver(drive, &idedisk_driver); > diff -uprN -X b/Documentation/dontdiff a/drivers/ide/ide-probe.c > b/drivers/ide/ide-probe.c > --- a/drivers/ide/ide-probe.c 2005-08-24 17:58:02.000000000 +0200 > +++ b/drivers/ide/ide-probe.c 2005-09-05 02:10:59.000000000 +0200 > @@ -1321,6 +1321,13 @@ static void drive_release_dev (struct de > drive->id = NULL; > } > drive->present = 0; > + > + /* Set the queue dead, so it won't call us anymore */ > + set_bit(QUEUE_FLAG_DEAD, &drive->queue->queue_flags); > + > + /* remove pointer to ide drive as it will be gone, soon */ > + drive->queue->queuedata = NULL; > + > /* Messed up locking ... */ > spin_unlock_irq(&ide_lock); > blk_cleanup_queue(drive->queue); > > > Signed-off-by: Thomas Kleffel <tk@maintech.de> > > Best regards, > Thomas - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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