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    Subject[PATCH 4.14 020/193] btrfs: sysfs: dont leak memory when failing add fsid
    Date
    From: Tobin C. Harding <tobin@kernel.org>

    commit e32773357d5cc271b1d23550b3ed026eb5c2a468 upstream.

    A failed call to kobject_init_and_add() must be followed by a call to
    kobject_put(). Currently in the error path when adding fs_devices we
    are missing this call. This could be fixed by calling
    btrfs_sysfs_remove_fsid() if btrfs_sysfs_add_fsid() returns an error or
    by adding a call to kobject_put() directly in btrfs_sysfs_add_fsid().
    Here we choose the second option because it prevents the slightly
    unusual error path handling requirements of kobject from leaking out
    into btrfs functions.

    Add a call to kobject_put() in the error path of kobject_add_and_init().
    This causes the release method to be called if kobject_init_and_add()
    fails. open_tree() is the function that calls btrfs_sysfs_add_fsid()
    and the error code in this function is already written with the
    assumption that the release method is called during the error path of
    open_tree() (as seen by the call to btrfs_sysfs_remove_fsid() under the
    fail_fsdev_sysfs label).

    Cc: stable@vger.kernel.org # v4.4+
    Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Tobin C. Harding <tobin@kernel.org>
    Reviewed-by: David Sterba <dsterba@suse.com>
    Signed-off-by: David Sterba <dsterba@suse.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/btrfs/sysfs.c | 7 ++++++-
    1 file changed, 6 insertions(+), 1 deletion(-)

    --- a/fs/btrfs/sysfs.c
    +++ b/fs/btrfs/sysfs.c
    @@ -794,7 +794,12 @@ int btrfs_sysfs_add_fsid(struct btrfs_fs
    fs_devs->fsid_kobj.kset = btrfs_kset;
    error = kobject_init_and_add(&fs_devs->fsid_kobj,
    &btrfs_ktype, parent, "%pU", fs_devs->fsid);
    - return error;
    + if (error) {
    + kobject_put(&fs_devs->fsid_kobj);
    + return error;
    + }
    +
    + return 0;
    }

    int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info)

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