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Subject[PATCH] extcon: modify extcon device to be created after driver data is set
Date
Currently, someone can invoke the sysfs such as state_show()
intermittently before 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>
---
drivers/extcon/extcon.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index d27cd9f88f86..74fee04bd764 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -1224,18 +1224,13 @@ 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;
- }
+ device_initialize(&edev->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;
}

@@ -1251,9 +1246,14 @@ int extcon_dev_register(struct extcon_dev *edev)
list_add(&edev->entry, &extcon_dev_list);
mutex_unlock(&extcon_dev_list_lock);

+ ret = device_add(&edev->dev);
+ if (ret)
+ goto err_dev;
+
return 0;

err_dev:
+ put_device(&edev->dev);
if (edev->max_supported)
kfree(edev->extcon_dev_type.groups);
err_alloc_groups:
--
2.32.0
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