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Message-ID: <1429245851.2850.76.camel@perches.com>
Date: Thu, 16 Apr 2015 21:44:11 -0700
From: Joe Perches <joe@...ches.com>
To: Sasha Levin <sasha.levin@...cle.com>
Cc: Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Guilherme Cox <cox@...puter.org>,
Tony Luck <tony.luck@...il.com>,
Xie XiuQi <xiexiuqi@...wei.com>
Subject: [PATCH] kasan: Show gcc version requirements in Kconfig and
Documentation
The documentation shows a need for gcc > 4.9.2, but it's
really >=. The Kconfig entries don't show require versions
so add them. Correct a latter/later typo too.
Signed-off-by: Joe Perches <joe@...ches.com>
---
(dropping Ingo from cc's)
On Thu, 2015-04-16 at 23:59 -0400, Sasha Levin wrote:
> On 04/16/2015 11:21 PM, Steven Rostedt wrote:
> > I have no idea what event caused the issue :-/
> 4.9.2+ is needed for KASan.
Perhaps the documentation and Kconfig entries could
describe that a bit better.
Documentation/kasan.txt | 6 +++---
lib/Kconfig.kasan | 6 ++++--
2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/Documentation/kasan.txt b/Documentation/kasan.txt
index 092fc10..3038b4b 100644
--- a/Documentation/kasan.txt
+++ b/Documentation/kasan.txt
@@ -9,7 +9,7 @@ a fast and comprehensive solution for finding use-after-free and out-of-bounds
bugs.
KASan uses compile-time instrumentation for checking every memory access,
-therefore you will need a certain version of GCC > 4.9.2
+therefore you will need a gcc version of 4.9.2 or later.
Currently KASan is supported only for x86_64 architecture and requires that the
kernel be built with the SLUB allocator.
@@ -23,8 +23,8 @@ To enable KASAN configure kernel with:
and choose between CONFIG_KASAN_OUTLINE and CONFIG_KASAN_INLINE. Outline/inline
is compiler instrumentation types. The former produces smaller binary the
-latter is 1.1 - 2 times faster. Inline instrumentation requires GCC 5.0 or
-latter.
+latter is 1.1 - 2 times faster. Inline instrumentation requires a gcc version
+of 5.0 or later.
Currently KASAN works only with the SLUB memory allocator.
For better bug detection and nicer report, enable CONFIG_STACKTRACE and put
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 4fecaedc..1e1c23e 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -10,8 +10,9 @@ config KASAN
help
Enables kernel address sanitizer - runtime memory debugger,
designed to find out-of-bounds accesses and use-after-free bugs.
- This is strictly debugging feature. It consumes about 1/8
- of available memory and brings about ~x3 performance slowdown.
+ This is strictly a debugging feature and it requires a gcc version
+ of 4.9.2 or later. It consumes about 1/8 of available memory and
+ brings about ~x3 performance slowdown.
For better error detection enable CONFIG_STACKTRACE,
and add slub_debug=U to boot cmdline.
@@ -40,6 +41,7 @@ config KASAN_INLINE
memory accesses. This is faster than outline (in some workloads
it gives about x2 boost over outline instrumentation), but
make kernel's .text size much bigger.
+ This requires a gcc version of 5.0 or later.
endchoice
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