block: Fix NULL pointer dereference in sd_revalidate_disk
Since 2.6.39 (1196f8b), when a driver returns -ENOMEDIUM for open(),
__blkdev_get() calls rescan_partitions() to remove
in-kernel partition structures and raise KOBJ_CHANGE uevent.
However it ends up calling driver's revalidate_disk without open
and could cause oops.
In the case of SCSI:
process A process B
----------------------------------------------
sys_open
__blkdev_get
sd_open
returns -ENOMEDIUM
scsi_remove_device
<scsi_device torn down>
rescan_partitions
sd_revalidate_disk
<oops>
Oopses are reported here:
http://marc.info/?l=linux-scsi&m=132388619710052
This patch separates the partition invalidation from rescan_partitions()
and use it for -ENOMEDIUM case.
Reported-by: Huajun Li <huajun.li.lee@gmail.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/partition-generic.c b/block/partition-generic.c
index d06ec1c..6df5d69 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -389,17 +389,11 @@
}
}
-int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
+static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
{
- struct parsed_partitions *state = NULL;
struct disk_part_iter piter;
struct hd_struct *part;
- int p, highest, res;
-rescan:
- if (state && !IS_ERR(state)) {
- kfree(state);
- state = NULL;
- }
+ int res;
if (bdev->bd_part_count)
return -EBUSY;
@@ -412,6 +406,24 @@
delete_partition(disk, part->partno);
disk_part_iter_exit(&piter);
+ return 0;
+}
+
+int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+ struct parsed_partitions *state = NULL;
+ struct hd_struct *part;
+ int p, highest, res;
+rescan:
+ if (state && !IS_ERR(state)) {
+ kfree(state);
+ state = NULL;
+ }
+
+ res = drop_partitions(disk, bdev);
+ if (res)
+ return res;
+
if (disk->fops->revalidate_disk)
disk->fops->revalidate_disk(disk);
check_disk_size_change(disk, bdev);
@@ -515,6 +527,26 @@
return 0;
}
+int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+ int res;
+
+ if (!bdev->bd_invalidated)
+ return 0;
+
+ res = drop_partitions(disk, bdev);
+ if (res)
+ return res;
+
+ set_capacity(disk, 0);
+ check_disk_size_change(disk, bdev);
+ bdev->bd_invalidated = 0;
+ /* tell userspace that the media / partition table may have changed */
+ kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+
+ return 0;
+}
+
unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
{
struct address_space *mapping = bdev->bd_inode->i_mapping;
