kmemcheck: rip it out

Fix up makefiles, remove references, and git rm kmemcheck.

Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@verizon.com
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

35 files changed, 7 insertions, 2592 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b74e13312fdc..00bb04972612 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1864,13 +1864,6 @@
                         Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
                         the default is off.
 
-        kmemcheck=      [X86] Boot-time kmemcheck enable/disable/one-shot mode
-                        Valid arguments: 0, 1, 2
-                        kmemcheck=0 (disabled)
-                        kmemcheck=1 (enabled)
-                        kmemcheck=2 (one-shot mode)
-                        Default: 2 (one-shot mode)
-
         kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
                         Default is 0 (don't ignore, but inject #GP)
 
diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst
index a81787cd47d7..e313925fb0fa 100644
--- a/Documentation/dev-tools/index.rst
+++ b/Documentation/dev-tools/index.rst
@@ -21,7 +21,6 @@ whole; patches welcome!
    kasan
    ubsan
    kmemleak
-   kmemcheck
    gdb-kernel-debugging
    kgdb
    kselftest
diff --git a/Documentation/dev-tools/kmemcheck.rst b/Documentation/dev-tools/kmemcheck.rst
deleted file mode 100644
index 7f3d1985de74..000000000000
--- a/Documentation/dev-tools/kmemcheck.rst
+++ /dev/null
@@ -1,733 +0,0 @@
-Getting started with kmemcheck
-==============================
-
-Vegard Nossum <vegardno@ifi.uio.no>
-
-
-Introduction
-------------
-
-kmemcheck is a debugging feature for the Linux Kernel. More specifically, it
-is a dynamic checker that detects and warns about some uses of uninitialized
-memory.
-
-Userspace programmers might be familiar with Valgrind's memcheck. The main
-difference between memcheck and kmemcheck is that memcheck works for userspace
-programs only, and kmemcheck works for the kernel only. The implementations
-are of course vastly different. Because of this, kmemcheck is not as accurate
-as memcheck, but it turns out to be good enough in practice to discover real
-programmer errors that the compiler is not able to find through static
-analysis.
-
-Enabling kmemcheck on a kernel will probably slow it down to the extent that
-the machine will not be usable for normal workloads such as e.g. an
-interactive desktop. kmemcheck will also cause the kernel to use about twice
-as much memory as normal. For this reason, kmemcheck is strictly a debugging
-feature.
-
-
-Downloading
------------
-
-As of version 2.6.31-rc1, kmemcheck is included in the mainline kernel.
-
-
-Configuring and compiling
--------------------------
-
-kmemcheck only works for the x86 (both 32- and 64-bit) platform. A number of
-configuration variables must have specific settings in order for the kmemcheck
-menu to even appear in "menuconfig". These are:
-
-- ``CONFIG_CC_OPTIMIZE_FOR_SIZE=n``
-        This option is located under "General setup" / "Optimize for size".
-
-        Without this, gcc will use certain optimizations that usually lead to
-        false positive warnings from kmemcheck. An example of this is a 16-bit
-        field in a struct, where gcc may load 32 bits, then discard the upper
-        16 bits. kmemcheck sees only the 32-bit load, and may trigger a
-        warning for the upper 16 bits (if they're uninitialized).
-
-- ``CONFIG_SLAB=y`` or ``CONFIG_SLUB=y``
-        This option is located under "General setup" / "Choose SLAB
-        allocator".
-
-- ``CONFIG_FUNCTION_TRACER=n``
-        This option is located under "Kernel hacking" / "Tracers" / "Kernel
-        Function Tracer"
-
-        When function tracing is compiled in, gcc emits a call to another
-        function at the beginning of every function. This means that when the
-        page fault handler is called, the ftrace framework will be called
-        before kmemcheck has had a chance to handle the fault. If ftrace then
-        modifies memory that was tracked by kmemcheck, the result is an
-        endless recursive page fault.
-
-- ``CONFIG_DEBUG_PAGEALLOC=n``
-        This option is located under "Kernel hacking" / "Memory Debugging"
-        / "Debug page memory allocations".
-
-In addition, I highly recommend turning on ``CONFIG_DEBUG_INFO=y``. This is also
-located under "Kernel hacking". With this, you will be able to get line number
-information from the kmemcheck warnings, which is extremely valuable in
-debugging a problem. This option is not mandatory, however, because it slows
-down the compilation process and produces a much bigger kernel image.
-
-Now the kmemcheck menu should be visible (under "Kernel hacking" / "Memory
-Debugging" / "kmemcheck: trap use of uninitialized memory"). Here follows
-a description of the kmemcheck configuration variables:
-
-- ``CONFIG_KMEMCHECK``
-        This must be enabled in order to use kmemcheck at all...
-
-- ``CONFIG_KMEMCHECK_``[``DISABLED`` | ``ENABLED`` | ``ONESHOT``]``_BY_DEFAULT``
-        This option controls the status of kmemcheck at boot-time. "Enabled"
-        will enable kmemcheck right from the start, "disabled" will boot the
-        kernel as normal (but with the kmemcheck code compiled in, so it can
-        be enabled at run-time after the kernel has booted), and "one-shot" is
-        a special mode which will turn kmemcheck off automatically after
-        detecting the first use of uninitialized memory.
-
-        If you are using kmemcheck to actively debug a problem, then you
-        probably want to choose "enabled" here.
-
-        The one-shot mode is mostly useful in automated test setups because it
-        can prevent floods of warnings and increase the chances of the machine
-        surviving in case something is really wrong. In other cases, the one-
-        shot mode could actually be counter-productive because it would turn
-        itself off at the very first error -- in the case of a false positive
-        too -- and this would come in the way of debugging the specific
-        problem you were interested in.
-
-        If you would like to use your kernel as normal, but with a chance to
-        enable kmemcheck in case of some problem, it might be a good idea to
-        choose "disabled" here. When kmemcheck is disabled, most of the run-
-        time overhead is not incurred, and the kernel will be almost as fast
-        as normal.
-
-- ``CONFIG_KMEMCHECK_QUEUE_SIZE``
-        Select the maximum number of error reports to store in an internal
-        (fixed-size) buffer. Since errors can occur virtually anywhere and in
-        any context, we need a temporary storage area which is guaranteed not
-        to generate any other page faults when accessed. The queue will be