Messages in this thread | | | Date | Fri, 21 Jan 2022 22:36:45 +0300 | Subject | Re: [PATCH] drivers: net: remove a dangling pointer in peak_usb_create_dev | From | Pavel Skripkin <> |
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Hi Dongliang,
On 1/21/22 08:58, Dongliang Mu wrote: [...]>> BTW, as you mentioned, dev->next_siblings is used in struct >> peak_usb_adapter::dev_free() (i.e., pcan_usb_fd_free or >> pcan_usb_pro_free), how about the following path? >> >> peak_usb_probe >> -> peak_usb_create_dev (goto adap_dev_free;) >> -> dev->adapter->dev_free() >> -> pcan_usb_fd_free or pcan_usb_pro_free (This function uses >> next_siblings as condition elements) >> >> static void pcan_usb_fd_free(struct peak_usb_device *dev) >> { >> /* last device: can free shared objects now */ >> if (!dev->prev_siblings && !dev->next_siblings) { >> struct pcan_usb_fd_device *pdev = >> container_of(dev, struct pcan_usb_fd_device, dev); >> >> /* free commands buffer */ >> kfree(pdev->cmd_buffer_addr); >> >> /* free usb interface object */ >> kfree(pdev->usb_if); >> } >> } >> >> If next_siblings is not NULL, will it lead to the missing free of >> cmd_buffer_addr and usb_if? > > The answer is No. Forget my silly thought. >
Yeah, it seems like (at least based on code), that this dangling pointer is not dangerous, since nothing accesses it. And next_siblings _guaranteed_ to be NULL, since dev->next_siblings is set NULL in disconnect()
With regards, Pavel Skripkin
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