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>
---
kernel/cgroup.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 155c88470543..3348a36c3694 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -258,6 +258,9 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css,
*/
static bool cgroup_ssid_enabled(int ssid)
{
+ if (CGROUP_SUBSYS_COUNT == 0)
+ return 0;
+
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
}
--
2.7.0
--
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