| Message ID | 20211018091116.16874-1-qiang.zhang1211@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: fix incorrect references to disk objects | expand |
On Mon, Oct 18, 2021 at 05:11:16PM +0800, Zqiang wrote: > --- 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); > + disk = NULL; > out_put_disk: > put_disk(disk); > return ERR_PTR(err); Stylistic nitpick: I think directly returning where this currently clears disk would be a little easier to follow.
diff --git a/block/partitions/core.c b/block/partitions/core.c index 3a4898433c43..4cb6803e7021 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); + disk = NULL; out_put_disk: put_disk(disk); return ERR_PTR(err);
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 making disk is NULL when calling put_disk(). Reported-by: Hao Sun <sunhao.th@gmail.com> Signed-off-by: Zqiang <qiang.zhang1211@gmail.com> --- block/partitions/core.c | 1 + 1 file changed, 1 insertion(+)