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Miroslav Lichvar 5a8c02a6bf ptp: Limit time setting of PTP clocks
Networking drivers implementing PTP clocks and kernel socket code
handling hardware timestamps use the 64-bit signed ktime_t type counting
nanoseconds. When a PTP clock reaches the maximum value in year 2262,
the timestamps returned to applications will overflow into year 1667.
The same thing happens when injecting a large offset with
clock_adjtime(ADJ_SETOFFSET).

The commit 7a8e61f847 ("timekeeping: Force upper bound for setting
CLOCK_REALTIME") limited the maximum accepted value setting the system
clock to 30 years before the maximum representable value (i.e. year
2232) to avoid the overflow, assuming the system will not run for more
than 30 years.

Enforce the same limit for PTP clocks. Don't allow negative values and
values closer than 30 years to the maximum value. Drivers may implement
an even lower limit if the hardware registers cannot represent the whole
interval between years 1970 and 2262 in the required resolution.

Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <jstultz@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250828103300.1387025-1-mlichvar@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-01 13:03:37 -07:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-08-29 11:48:01 -07:00
block block: avoid cpu_hotplug_lock depedency on freeze_lock 2025-08-21 07:11:11 -06:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-08-29 11:48:01 -07:00
drivers ptp: Limit time setting of PTP clocks 2025-09-01 13:03:37 -07:00
fs Driver core fixes for 6.16-rc3 2025-08-23 09:04:32 -04:00
include tcp: Remove sk->sk_prot->orphan_count. 2025-09-01 12:52:09 -07:00
init Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
io_uring Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-08-29 11:48:01 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-08-29 11:48:01 -07:00
lib Crypto library fixes for v6.17-rc3 2025-08-21 04:54:01 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-08-29 11:48:01 -07:00
net tcp: Remove sk->sk_prot->orphan_count. 2025-09-01 12:52:09 -07:00
rust Driver core fixes for 6.16-rc3 2025-08-23 09:04:32 -04:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts uapi: wrap compiler_types.h in an ifdef instead of the implicit strip 2025-08-28 13:06:48 +02:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: usb-audio: Use correct sub-type for UAC3 feature unit validation 2025-08-21 17:10:14 +02:00
tools vsock/test: Remove redundant semicolons 2025-08-29 19:10:52 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap .mailmap: add entry for Easwar Hariharan 2025-08-19 16:35:55 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: retire Boris from TLS maintainers 2025-08-26 17:36:01 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-08-29 11:48:01 -07:00
Makefile Linux 6.17-rc3 2025-08-24 12:04:12 -04:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.