mirror of
https://github.com/torvalds/linux.git
synced 2026-07-28 01:55:51 +02:00
Linux kernel source tree
aa9f09a26b
Russell King says: ==================== ptp: safely cleanup when unregistering a PTP clock The standard rule in the kernel for unregistering user visible devices is to unpublish the userspace API before doing any shutdown of the resources necessary for the operation of the device. PTP has several issues in this area: 1. ptp_clock_unregister() cancells and destroys work while the PTP chardev is still published, which gives the opportunity for a precisely timed user API call to cause a driver to attempt to queue the aux work. 2. PTP pins are not cleaned up - if userspace has enabled PTP pins, e.g. for extts, drivers are forced to do cleanup before calling ptp_clock_unregister() to stop events being forwarded into the PTP layer. E.g mv88e6xxx cancells its internal tai_event_work to avoid calling into the PTP clock code with a stale ptp_clock pointer, but a badly timed userspace EXTTS enable will re-schedule the tai_event_work. Simplify the process by ensuring that: 1. we take a referene on the PTP struct device to stop the ptp_clock structure going away underneath us when we call posix_clock_unregister(). 2. call posix_clock_unregister() to remove the /dev/ptp* device. 3. add additional functionality to disable any PTP EXTTS pins and PPS event generation that have been configured on this device. This should shutdown all events coming from PTP clock drivers. 4. cancel the delayed aux_work and destroy the kthread. 5. remove the PPS source. 6. drop the reference on the PTP struct device to allow the ptp_clock structure to be released. This is difficult for me to test beyond build testing - on the Clearfog platform with Marvell PHY PTP, the ethernet PHY is the primary connectivity, so removing the PHY driver for an in-use network interface isn't possible. On the ZII rev B platform, where the DSA switches have the TAI hardware and where root NFS is used, removal of the DSA switch module somehow forces the FEC interface _not_ connected to the DSA switch to lose link, causing the machine to become unresponsive as its root filesystem vanishes. ==================== Link: https://patch.msgid.link/aMnYIu7RbgfXrmGx@shell.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.