On Tue, Sep 12, 2023 at 12:27:06AM +0800, Chen Yu wrote:
> The following NULL pointer exception was found during boot up:
>
> calling ucsi_acpi_platform_driver_init+0x0/0xff0 [ucsi_acpi] @ 394
> initcall mac_hid_init+0x0/0xff0 [mac_hid] returned 0 after 5 usecs
> BUG: kernel NULL pointer dereference, address: 0000000000000020
> Call Trace:
> ? ucsi_debugfs_unregister+0x15/0x30 [typec_ucsi]
> ucsi_destroy+0x17/0x30 [typec_ucsi]
> ucsi_acpi_probe+0x1d5/0x230 [ucsi_acpi]
>
> It is possible that ucsi_acpi_probe() fails to install the notifier,
> and calls ucsi_destroy() to release the resource. However at that
> moment the debugfs has not been registered yet, thus the NULL pointer
> exception is triggered. Add the check for debugfs pointer.
>
> Fixes: Commit df0383ffad64 ("usb: typec: ucsi: Add debugfs for ucsi commands")
Incorrect format :(
> Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
> ---
> drivers/usb/typec/ucsi/debugfs.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/ucsi/debugfs.c b/drivers/usb/typec/ucsi/debugfs.c
> index 0c7bf88d4a7f..55533dc3d539 100644
> --- a/drivers/usb/typec/ucsi/debugfs.c
> +++ b/drivers/usb/typec/ucsi/debugfs.c
> @@ -84,7 +84,8 @@ void ucsi_debugfs_register(struct ucsi *ucsi)
>
> void ucsi_debugfs_unregister(struct ucsi *ucsi)
> {
> - debugfs_remove_recursive(ucsi->debugfs->dentry);
> + if (ucsi->debugfs)
> + debugfs_remove_recursive(ucsi->debugfs->dentry);
> kfree(ucsi->debugfs);
> }
What's wrong with this patch instead:
https://lore.kernel.org/all/20230906084842.1922052-1-heikki.krogerus@xxxxxxxxxxxxxxx/
thanks,
greg k-h
