Hello,
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().
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.
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 <[email protected]>
Best regards,
Thomas
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