abee7c494d
When running in lazy TLB mode the currently active page tables might
be the ones of a previous process, e.g. when running a kernel thread.
This can be problematic in case kernel code is being modified via
text_poke() in a kernel thread, and on another processor exit_mmap()
is active for the process which was running on the first cpu before
the kernel thread.
As text_poke() is using a temporary address space and the former
address space (obtained via cpu_tlbstate.loaded_mm) is restored
afterwards, there is a race possible in case the cpu on which
exit_mmap() is running wants to make sure there are no stale
references to that address space on any cpu active (this e.g. is
required when running as a Xen PV guest, where this problem has been
observed and analyzed).
In order to avoid that, drop off TLB lazy mode before switching to the
temporary address space.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 Restructured Text 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.