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    Subject[PATCH 4.19 260/287] extcon: Modify extcon device to be created after driver data is set
    Date
    From: bumwoo lee <bw365.lee@samsung.com>

    [ Upstream commit 5dcc2afe716d69f5112ce035cb14f007461ff189 ]

    Currently, someone can invoke the sysfs such as state_show()
    intermittently before dev_set_drvdata() is done.
    And it can be a cause of kernel Oops because of edev is Null at that time.
    So modified the driver registration to after setting drviver data.

    - Oops's backtrace.

    Backtrace:
    [<c067865c>] (state_show) from [<c05222e8>] (dev_attr_show)
    [<c05222c0>] (dev_attr_show) from [<c02c66e0>] (sysfs_kf_seq_show)
    [<c02c6648>] (sysfs_kf_seq_show) from [<c02c496c>] (kernfs_seq_show)
    [<c02c4938>] (kernfs_seq_show) from [<c025e2a0>] (seq_read)
    [<c025e11c>] (seq_read) from [<c02c50a0>] (kernfs_fop_read)
    [<c02c5064>] (kernfs_fop_read) from [<c0231cac>] (__vfs_read)
    [<c0231c5c>] (__vfs_read) from [<c0231ee0>] (vfs_read)
    [<c0231e34>] (vfs_read) from [<c0232464>] (ksys_read)
    [<c02323f0>] (ksys_read) from [<c02324fc>] (sys_read)
    [<c02324e4>] (sys_read) from [<c00091d0>] (__sys_trace_return)

    Signed-off-by: bumwoo lee <bw365.lee@samsung.com>
    Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/extcon/extcon.c | 29 +++++++++++++++++------------
    1 file changed, 17 insertions(+), 12 deletions(-)

    diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
    index e70f21ae85ff..4c70136c7aa3 100644
    --- a/drivers/extcon/extcon.c
    +++ b/drivers/extcon/extcon.c
    @@ -1245,19 +1245,14 @@ int extcon_dev_register(struct extcon_dev *edev)
    edev->dev.type = &edev->extcon_dev_type;
    }

    - ret = device_register(&edev->dev);
    - if (ret) {
    - put_device(&edev->dev);
    - goto err_dev;
    - }
    -
    spin_lock_init(&edev->lock);
    - edev->nh = devm_kcalloc(&edev->dev, edev->max_supported,
    - sizeof(*edev->nh), GFP_KERNEL);
    - if (!edev->nh) {
    - ret = -ENOMEM;
    - device_unregister(&edev->dev);
    - goto err_dev;
    + if (edev->max_supported) {
    + edev->nh = kcalloc(edev->max_supported, sizeof(*edev->nh),
    + GFP_KERNEL);
    + if (!edev->nh) {
    + ret = -ENOMEM;
    + goto err_alloc_nh;
    + }
    }

    for (index = 0; index < edev->max_supported; index++)
    @@ -1268,6 +1263,12 @@ int extcon_dev_register(struct extcon_dev *edev)
    dev_set_drvdata(&edev->dev, edev);
    edev->state = 0;

    + ret = device_register(&edev->dev);
    + if (ret) {
    + put_device(&edev->dev);
    + goto err_dev;
    + }
    +
    mutex_lock(&extcon_dev_list_lock);
    list_add(&edev->entry, &extcon_dev_list);
    mutex_unlock(&extcon_dev_list_lock);
    @@ -1275,6 +1276,9 @@ int extcon_dev_register(struct extcon_dev *edev)
    return 0;

    err_dev:
    + if (edev->max_supported)
    + kfree(edev->nh);
    +err_alloc_nh:
    if (edev->max_supported)
    kfree(edev->extcon_dev_type.groups);
    err_alloc_groups:
    @@ -1335,6 +1339,7 @@ void extcon_dev_unregister(struct extcon_dev *edev)
    if (edev->max_supported) {
    kfree(edev->extcon_dev_type.groups);
    kfree(edev->cables);
    + kfree(edev->nh);
    }

    put_device(&edev->dev);
    --
    2.35.1


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