diff options
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 19 |
1 files changed, 19 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); |