diff options
| -rw-r--r-- | block/genhd.c | 19 | ||||
| -rw-r--r-- | block/partition-generic.c | 7 | ||||
| -rw-r--r-- | include/linux/genhd.h | 1 |
3 files changed, 27 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c index 1d0d25f7b0fe..83f5c33d1e80 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -531,6 +531,18 @@ void blk_free_devt(dev_t devt) } } +/** + * We invalidate devt by assigning NULL pointer for devt in idr. + */ +void blk_invalidate_devt(dev_t devt) +{ + if (MAJOR(devt) == BLOCK_EXT_MAJOR) { + spin_lock_bh(&ext_devt_lock); + idr_replace(&ext_devt_idr, NULL, blk_mangle_minor(MINOR(devt))); + spin_unlock_bh(&ext_devt_lock); + } +} + static char *bdevt_str(dev_t devt, char *buf) { if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { @@ -793,6 +805,13 @@ void del_gendisk(struct gendisk *disk) if (!(disk->flags & GENHD_FL_HIDDEN)) blk_unregister_region(disk_devt(disk), disk->minors); + /* + * Remove gendisk pointer from idr so that it cannot be looked up + * while RCU period before freeing gendisk is running to prevent + * use-after-free issues. Note that the device number stays + * "in-use" until we really free the gendisk. + */ + blk_invalidate_devt(disk_devt(disk)); kobject_put(disk->part0.holder_dir); kobject_put(disk->slave_dir); diff --git a/block/partition-generic.c b/block/partition-generic.c index 8e596a8dff32..aee643ce13d1 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -285,6 +285,13 @@ void delete_partition(struct gendisk *disk, int partno) kobject_put(part->holder_dir); device_del(part_to_dev(part)); + /* + * Remove gendisk pointer from idr so that it cannot be looked up + * while RCU period before freeing gendisk is running to prevent + * use-after-free issues. Note that the device number stays + * "in-use" until we really free the gendisk. + */ + blk_invalidate_devt(part_devt(part)); hd_struct_kill(part); } diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 6547c9256d5c..8b5330dd5ac0 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -617,6 +617,7 @@ struct unixware_disklabel { extern int blk_alloc_devt(struct hd_struct *part, dev_t *devt); extern void blk_free_devt(dev_t devt); +extern void blk_invalidate_devt(dev_t devt); extern dev_t blk_lookup_devt(const char *name, int partno); extern char *disk_name (struct gendisk *hd, int partno, char *buf); |