[PATCH 07/16] cgroup: fix warning when building without any subsys
Arnd Bergmann
arnd at arndb.de
Fri Oct 5 10:55:21 EDT 2012
In a configuration where the base cgroup support is enabled but
every single cgroup subsys is turned off, CGROUP_BUILTIN_SUBSYS_COUNT
is zero, which causes the sanity check code in cgroup_load_subsys
to trigger:
BUG_ON(ss->subsys_id >= CGROUP_BUILTIN_SUBSYS_COUNT);
BUG_ON(subsys[ss->subsys_id] != ss);
Gcc first confirms that subsys_id cannot be 0 or larger and consequently
warns in the second line.
kernel/cgroup.c: In function 'cgroup_load_subsys':
kernel/cgroup.c:4326:38: warning: array subscript is below array bounds [-Warray-bounds]
Since the subsys_id can never be less than zero, we can just change the
type to an unsigned int, which makes the warning go away.
Found by building ARM cns3420vb_defconfig.
Signed-off-by: Arnd Bergmann <arnd at arndb.de>
Cc: Tejun Heo <tj at kernel.org>
Cc: Li Zefan <lizefan at huawei.com>
Cc: Ben Blum <bblum at andrew.cmu.edu>
---
include/linux/cgroup.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c90eaa8..26b99df 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -475,7 +475,7 @@ struct cgroup_subsys {
void (*post_clone)(struct cgroup *cgrp);
void (*bind)(struct cgroup *root);
- int subsys_id;
+ unsigned int subsys_id;
int active;
int disabled;
int early_init;
--
1.7.10
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