Messages in this thread |  | | Date | Fri, 27 Dec 2019 07:02:19 -0800 | From | Richard Cochran <> | Subject | Re: [PATCH v2] ptp: fix the race between the release of ptp_clock and cdev |
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On Fri, Dec 27, 2019 at 03:26:27AM +0100, Vladis Dronov wrote: > Here cdev is embedded in posix_clock which is embedded in ptp_clock. > The race happens because ptp_clock's lifetime is controlled by two > refcounts: kref and cdev.kobj in posix_clock. This is wrong. > > Make ptp_clock's sysfs device a parent of cdev with cdev_device_add() > created especially for such cases. This way the parent device with its > ptp_clock is not released until all references to the cdev are released. > This adds a requirement that an initialized but not exposed struct > device should be provided to posix_clock_register() by a caller instead > of a simple dev_t. > > This approach was adopted from the commit 72139dfa2464 ("watchdog: Fix > the race between the release of watchdog_core_data and cdev"). See > details of the implementation in the commit 233ed09d7fda ("chardev: add > helper function to register char devs with a struct device").
Thanks for digging into this!
Acked-by: Richard Cochran <richardcochran@gmail.com>
> /** > * posix_clock_register() - register a new clock > - * @clk: Pointer to the clock. Caller must provide 'ops' and 'release' > - * @devid: Allocated device id > + * @clk: Pointer to the clock. Caller must provide 'ops' field > + * @dev: Pointer to the initialized device. Caller must provide > + * 'release' filed
field
Thanks, Richard
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