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Thomas Gleixner 67edab48ca posix-timers: Handle relative posix-timers correctly
The recent rework of the posix timer internals broke the magic posix
mechanism, which requires that relative timers are not affected by
modifications of the underlying clock. That means relative CLOCK_REALTIME
timers cannot use CLOCK_REALTIME, because that can be set and adjusted. The
underlying hrtimer switches the clock for these timers to CLOCK_MONOTONIC.

That still works, but reading the remaining time of such a timer has been
broken in the rework. The old code used the hrtimer internals directly and
avoided the posix clock callbacks. Now common_timer_get() uses the
underlying kclock->timer_get() callback, which is still CLOCK_REALTIME
based. So the remaining time of such a timer is calculated against the
wrong time base.

Handle it by switching the k_itimer->kclock pointer according to the
resulting hrtimer mode. k_itimer->it_clock still contains CLOCK_REALTIME
because the timer might be set with ABSTIME later and then it needs to
switch back to the realtime posix clock implementation.

Fixes: eae1c4ae27 ("posix-timers: Make use of cancel/arm callbacks")
Reported-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/20170609201156.GB21491@outlook.office365.com
2017-06-12 21:07:41 +02:00
arch Merge branch 'timers/urgent' into WIP.timers 2017-06-04 15:21:52 +02:00
block block: Avoid that blk_exit_rl() triggers a use-after-free 2017-06-01 13:07:55 -06:00
certs
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Documentation Pin control fixes for v4.12: 2017-05-29 10:05:19 -07:00
drivers Merge branch 'timers/urgent' into WIP.timers 2017-06-04 15:21:52 +02:00
firmware
fs Merge branch 'akpm' (patches from Andrew) 2017-06-02 15:49:46 -07:00
include posix-timers: Add active flag to k_itimer 2017-06-04 15:40:26 +02:00
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kernel posix-timers: Handle relative posix-timers correctly 2017-06-12 21:07:41 +02:00
lib test_bpf: Add a couple of tests for BPF_JSGE. 2017-05-25 14:37:56 -04:00
mm mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-26 13:51:01 -07:00
samples
scripts scripts/gdb: make lx-dmesg command work (reliably) 2017-06-02 15:07:38 -07:00
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sound sound fixes for 4.12-rc4 2017-06-02 09:40:47 -07:00
tools powerpc fixes for 4.12 #4 2017-05-27 09:28:34 -07:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
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MAINTAINERS TTY/Serial fixes for 4.12-rc3 2017-05-27 09:39:09 -07:00
Makefile Linux 4.12-rc3 2017-05-28 17:20:53 -07:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.