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05 April 2024, 19:05:47 UTC
Revision a810007afe239d59c1115fcaa06eb5b480f876e9 authored by Sean Rees on 08 February 2017, 22:30:59 UTC, committed by Linus Torvalds on 08 February 2017, 23:41:43 UTC 
mm/slub.c: fix random_seq offset destruction
 
Commit 210e7a43fa90 ("mm: SLUB freelist randomization") broke USB hub
initialisation as described in

  https://bugzilla.kernel.org/show_bug.cgi?id=177551.

Bail out early from init_cache_random_seq if s->random_seq is already
initialised.  This prevents destroying the previously computed
random_seq offsets later in the function.

If the offsets are destroyed, then shuffle_freelist will truncate
page->freelist to just the first object (orphaning the rest).

Fixes: 210e7a43fa90 ("mm: SLUB freelist randomization")
Link: http://lkml.kernel.org/r/20170207140707.20824-1-sean@erifax.org
Signed-off-by: Sean Rees <sean@erifax.org>
Reported-by: <userwithuid@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 4d59b6c
Raw File
Tip revision: a810007afe239d59c1115fcaa06eb5b480f876e9 authored by Sean Rees on 08 February 2017, 22:30:59 UTC
mm/slub.c: fix random_seq offset destruction
Tip revision: a810007
gcc-plugin.sh 
#!/bin/sh
srctree=$(dirname "$0")

SHOW_ERROR=
if [ "$1" = "--show-error" ] ; then
	SHOW_ERROR=1
	shift || true
fi

gccplugins_dir=$($3 -print-file-name=plugin)
plugincc=$($1 -E -x c++ - -o /dev/null -I"${srctree}"/gcc-plugins -I"${gccplugins_dir}"/include 2>&1 <<EOF
#include "gcc-common.h"
#if BUILDING_GCC_VERSION >= 4008 || defined(ENABLE_BUILD_WITH_CXX)
#warning $2 CXX
#else
#warning $1 CC
#endif
EOF
)

if [ $? -ne 0 ]
then
	if [ -n "$SHOW_ERROR" ] ; then
		echo "${plugincc}" >&2
	fi
	exit 1
fi

case "$plugincc" in
	*"$1 CC"*)
		echo "$1"
		exit 0
		;;

	*"$2 CXX"*)
		# the c++ compiler needs another test, see below
		;;

	*)
		exit 1
		;;
esac

# we need a c++ compiler that supports the designated initializer GNU extension
plugincc=$($2 -c -x c++ -std=gnu++98 - -fsyntax-only -I"${srctree}"/gcc-plugins -I"${gccplugins_dir}"/include 2>&1 <<EOF
#include "gcc-common.h"
class test {
public:
	int test;
} test = {
	.test = 1
};
EOF
)

if [ $? -eq 0 ]
then
	echo "$2"
	exit 0
fi

if [ -n "$SHOW_ERROR" ] ; then
	echo "${plugincc}" >&2
fi
exit 1
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