This is a note to let you know that I've just added the patch titled
cgroup: avoid false positive gcc-6 warning
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cgroup-avoid-false-positive-gcc-6-warning.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cfe02a8a973e7e5f66926b8ae38dfce404b19e29 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Tue, 15 Mar 2016 00:21:06 +0100
Subject: cgroup: avoid false positive gcc-6 warning
From: Arnd Bergmann <arnd@xxxxxxxx>
commit cfe02a8a973e7e5f66926b8ae38dfce404b19e29 upstream.
When all subsystems are disabled, gcc notices that cgroup_subsys_enabled_key
is a zero-length array and that any access to it must be out of bounds:
In file included from ../include/linux/cgroup.h:19:0,
from ../kernel/cgroup.c:31:
../kernel/cgroup.c: In function 'cgroup_add_cftypes':
../kernel/cgroup.c:261:53: error: array subscript is above array bounds [-Werror=array-bounds]
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
../include/linux/jump_label.h:271:40: note: in definition of macro 'static_key_enabled'
static_key_count((struct static_key *)x) > 0; \
^
We should never call the function in this particular case, so this is
not a bug. In order to silence the warning, this adds an explicit check
for the CGROUP_SUBSYS_COUNT==0 case.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup.c | 3 +++
1 file changed, 3 insertions(+)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -236,6 +236,9 @@ static int cgroup_addrm_files(struct cgr
*/
static bool cgroup_ssid_enabled(int ssid)
{
+ if (CGROUP_SUBSYS_COUNT == 0)
+ return false;
+
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
}
Patches currently in stable-queue which might be from arnd@xxxxxxxx are
queue-4.4/drm-exynos-fix-error-handling-in-exynos_drm_subdrv_open.patch
queue-4.4/arm-8584-1-floppy-avoid-gcc-6-warning.patch
queue-4.4/powerpc-ptrace-fix-out-of-bounds-array-access-warning.patch
queue-4.4/cgroup-avoid-false-positive-gcc-6-warning.patch
queue-4.4/smc91x-avoid-self-comparison-warning.patch
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