Messages in this thread | | | Subject | Re: [PATCH v4 07/18] nitro_enclaves: Init misc device providing the ioctl interface | From | "Paraschiv, Andra-Irina" <> | Date | Tue, 30 Jun 2020 12:08:18 +0300 |
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On 30/06/2020 11:05, Greg KH wrote: > > On Mon, Jun 29, 2020 at 08:45:25PM +0300, Paraschiv, Andra-Irina wrote: >> >> On 29/06/2020 19:20, Greg KH wrote: >>> On Mon, Jun 22, 2020 at 11:03:18PM +0300, Andra Paraschiv wrote: >>>> +static int __init ne_init(void) >>>> +{ >>>> + struct pci_dev *pdev = pci_get_device(PCI_VENDOR_ID_AMAZON, >>>> + PCI_DEVICE_ID_NE, NULL); >>>> + int rc = -EINVAL; >>>> + >>>> + if (!pdev) >>>> + return -ENODEV; >>> Ick, that's a _very_ old-school way of binding to a pci device. Please >>> just be a "real" pci driver and your probe function will be called if >>> your hardware is present (or when it shows up.) To do it this way >>> prevents your driver from being auto-loaded for when your hardware is >>> seen in the system, as well as lots of other things. >> This check is mainly here in the case any codebase is added before the pci >> driver register call below. > What do you mean by "codebase"? You control this driver, just do all of > the logic in the probe() function, no need to do this in the module init > call. > >> And if we log any error with dev_err() instead of pr_err() before the driver >> register. > Don't do that. > >> That check was only for logging purposes, if done with dev_err(). I removed >> the check in v5. > Again, don't do it :) > >>>> + >>>> + if (!zalloc_cpumask_var(&ne_cpu_pool.avail, GFP_KERNEL)) >>>> + return -ENOMEM; >>>> + >>>> + mutex_init(&ne_cpu_pool.mutex); >>>> + >>>> + rc = pci_register_driver(&ne_pci_driver); >>> Nice, you did it right here, but why the above crazy test? >>> >>>> + if (rc < 0) { >>>> + dev_err(&pdev->dev, >>>> + "Error in pci register driver [rc=%d]\n", rc); >>>> + >>>> + goto free_cpumask; >>>> + } >>>> + >>>> + return 0; >>> You leaked a reference on that pci device, didn't you? Not good :( >> Yes, the pci get device call needs its pair - pci_dev_put(). I added it here >> and for the other occurrences where it was missing. > Again, just don't do it and then you don't have to worry about any of > this.
Yup, already started this morning to check & update where we can go without this call to get a PCI device reference, as a follow-up to what we discussed yesterday.
Thanks, Andra
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