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block: partition: initialize percpuref before sending out KOBJ_ADD

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commit b30a337ca2 upstream.

The initialization of partition's percpu_ref should have been done before
sending out KOBJ_ADD uevent, which may cause userspace to read partition
table. So 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)
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ming Lei 2016-03-30 08:46:31 +08:00 committed by Greg Kroah-Hartman
parent 8c9aef03d3
commit 5b616a05de
1 changed files with 10 additions and 3 deletions
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13
block/partition-generic.c
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@ -349,15 +349,20 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
goto out_del;
}
err = hd_ref_init(p);
if (err) {
if (flags & ADDPART_FLAG_WHOLEDISK)
goto out_remove_file;
goto out_del;
}
/* 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);
@ -366,6 +371,8 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
out_free:
kfree(p);
return ERR_PTR(err);
out_remove_file:
device_remove_file(pdev, &dev_attr_whole_disk);
out_del:
kobject_put(p->holder_dir);
device_del(pdev);