| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 001/163] block: partition: initialize percpuref before sending out KOBJ_ADD | Date | Mon, 2 May 2016 17:10:29 -0700 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei <ming.lei@canonical.com>
commit b30a337ca27c4f40439e4bfb290cba5f88d73bb7 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>
--- block/partition-generic.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
--- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -349,15 +349,20 @@ struct hd_struct *add_partition(struct g 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 @@ out_free_stats: 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);
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