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f8fc36851c
The VDSO update for CLOCK_BOOTTIME has a overflow issue as it shifts the nanoseconds based boot time offset left by the clocksource shift. That overflows once the boot time offset becomes large enough. As a consequence CLOCK_BOOTTIME in the VDSO becomes a random number causing applications to misbehave. Fix it by storing a timespec64 representation of the offset when boot time is adjusted and add that to the MONOTONIC base time value in the vdso data page. Using the timespec64 representation avoids a 64bit division in the update code. Fixes:44f57d788e("timekeeping: Provide a generic update_vsyscall() implementation") Reported-by: Chris Clayton <chris2553@googlemail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Chris Clayton <chris2553@googlemail.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908221257580.1983@nanos.tec.linutronix.de (cherry picked from commitb99328a60a) Signed-off-by: Greg Kroah-Hartman <gregkh@google.com> Change-Id: I61f5da6821a95b4cb855f737ef0dc94acbb1ccfe
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 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.