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SubjectRe: [PATCH v1] block: partition: initialize percpuref before new partition is visiable
On 2016-03-31 04:40, Ming Lei wrote:
> The initialization of partition's percpu_ref should have been done
> before
> the new partition is updated to partition table via
> rcu_assign_pointer(), otherwise the uninitialized percpu_ref may be
> accessed
> in data path.
>
> This patch fixes this issue reported by Naveen.
>
> Reported-by: Naveen Kaje <nkaje@codeaurora.org>
> Tested-by: Naveen Kaje <nkaje@codeaurora.org>
> Fixes: 6c71013ecb7e2(block: partition: convert percpu ref)
> Cc: <stable@vger.kernel.org> # v4.3+
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> ---
> V1:
> - put 'if' around the actual device_remove_file at the label
> as suggested by Christoph
> - make commit log more accurate
>
> block/partition-generic.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/block/partition-generic.c b/block/partition-generic.c
> index 5d87019..54d4be8 100644
> --- a/block/partition-generic.c
> +++ b/block/partition-generic.c
> @@ -361,15 +361,17 @@ struct hd_struct *add_partition(struct gendisk
> *disk, int partno,
> goto out_del;
> }
>
> + err = hd_ref_init(p);
> + if (err)
> + goto out_remove_file;
> +
> /* everything is up and running, commence */
> rcu_assign_pointer(ptbl->part[partno], p);
>
> /* suppress uevent if the disk suppresses it */
> if (!dev_get_uevent_suppress(ddev))
> kobject_uevent(&pdev->kobj, KOBJ_ADD);
> -
> - if (!hd_ref_init(p))
> - return p;
> + return p;
>
> out_free_info:
> free_part_info(p);
> @@ -378,6 +380,9 @@ out_free_stats:
> out_free:
> kfree(p);
> return ERR_PTR(err);
> +out_remove_file:
> + if (flags & ADDPART_FLAG_WHOLEDISK)
> + device_remove_file(pdev, &dev_attr_whole_disk);
> out_del:
> kobject_put(p->holder_dir);
> device_del(pdev);

Looks good,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

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