From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Kleffel Subject: [PATCH] fix kernel oops, when IDE-Device (CF-Card) is removed while mounted. Date: Tue, 06 Sep 2005 20:54:32 +0200 Message-ID: <431DE5E8.8000703@maintech.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: B.Zolnierkiewicz@elka.pw.edu.pl Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org List-Id: linux-ide@vger.kernel.org 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 Best regards, Thomas