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Filename Latest commit message Latest commit date
Dave Hansen 0d83432811 mm: Allow non-direct-map arguments to free_reserved_area()
free_reserved_area() takes pointers as arguments to show which addresses
should be freed.  However, it does this in a somewhat ambiguous way.  If it
gets a kernel direct map address, it always works.  However, if it gets an
address that is part of the kernel image alias mapping, it can fail.

It fails if all of the following happen:
 * The specified address is part of the kernel image alias
 * Poisoning is requested (forcing a memset())
 * The address is in a read-only portion of the kernel image

The memset() fails on the read-only mapping, of course.
free_reserved_area() *is* called both on the direct map and on kernel image
alias addresses.  We've just lucked out thus far that the kernel image
alias areas it gets used on are read-write.  I'm fairly sure this has been
just a happy accident.

It is quite easy to make free_reserved_area() work for all cases: just
convert the address to a direct map address before doing the memset(), and
do this unconditionally.  There is little chance of a regression here
because we previously did a virt_to_page() on the address for the memset,
so we know these are not highmem pages for which virt_to_page() would fail.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@google.com
Cc: aarcange@redhat.com
Cc: jgross@suse.com
Cc: jpoimboe@redhat.com
Cc: gregkh@linuxfoundation.org
Cc: peterz@infradead.org
Cc: hughd@google.com
Cc: torvalds@linux-foundation.org
Cc: bp@alien8.de
Cc: luto@kernel.org
Cc: ak@linux.intel.com
Cc: Kees Cook <keescook@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20180802225826.1287AE3E@viggo.jf.intel.com
2018-08-05 22:21:02 +02:00
arch x86/mm/pti: Clear Global bit more aggressively 2018-08-05 22:21:02 +02:00
block Partially revert "block: fail op_is_write() requests to read-only partitions" 2018-08-04 18:19:55 -07:00
certs
crypto
Documentation
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-08-05 08:20:39 -07:00
firmware
fs - Fix JFS usercopy whitelist (it needed to cover neighboring field too) for 2018-08-04 18:34:55 -07:00
include
init
ipc
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-05 09:25:29 -07:00
lib
LICENSES
mm mm: Allow non-direct-map arguments to free_reserved_area() 2018-08-05 22:21:02 +02:00
net netlink: Don't shift on 64 for ngroups 2018-08-04 17:52:51 -07:00
samples
scripts
security
sound
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-05 09:13:07 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS ARC updates for 4.18 2018-08-02 16:52:50 -07:00
Makefile Linux 4.18-rc8 2018-08-05 12:37:41 -07:00
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.
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.