When adding partitions to the disk, the reference count of the disk object is increased. then alloc partition device and called device_add(), if the device_add() return error, the reference count of the disk object will be reduced twice, at put_device(pdev) and put_disk(disk). this leads to the end of the object's life cycle prematurely, and trigger following calltrace. __init_work+0x2d/0x50 kernel/workqueue.c:519 synchronize_rcu_expedited+0x3af/0x650 kernel/rcu/tree_exp.h:847 bdi_remove_from_list mm/backing-dev.c:938 [inline] bdi_unregister+0x17f/0x5c0 mm/backing-dev.c:946 release_bdi+0xa1/0xc0 mm/backing-dev.c:968 kref_put include/linux/kref.h:65 [inline] bdi_put+0x72/0xa0 mm/backing-dev.c:976 bdev_free_inode+0x11e/0x220 block/bdev.c:408 i_callback+0x3f/0x70 fs/inode.c:226 rcu_do_batch kernel/rcu/tree.c:2508 [inline] rcu_core+0x76d/0x16c0 kernel/rcu/tree.c:2743 __do_softirq+0x1d7/0x93b kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu kernel/softirq.c:636 [inline] irq_exit_rcu+0xf2/0x130 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 Return directly after calling the put_device(). Reported-by: Hao Sun <sunhao.th@xxxxxxxxx> Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx> --- v1->v2: directly returning instead of assigning disk to NULL v2->v3: modify description information block/partitions/core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/partitions/core.c b/block/partitions/core.c index 9dbddc355b40..ed5deef1d7e1 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -424,6 +424,7 @@ static struct block_device *add_partition(struct gendisk *disk, int partno, device_del(pdev); out_put: put_device(pdev); + return ERR_PTR(err); out_put_disk: put_disk(disk); return ERR_PTR(err); -- 2.17.1
