When CONFIG_DEBUG_VM is set, the various VM_BUG_ON() confuse gcc to the point where it cannot remember that 'memcg' is known to be initialized:
mm/memcontrol.c: In function 'mem_cgroup_can_attach': mm/memcontrol.c:4791:9: warning: 'memcg' may be used uninitialized in this function [-Wmaybe-uninitialized] On ARM gcc-5.1, the above happens when any two or more of the VM_BUG_ON() are active, but not when I remove most or all of them. This is clearly random behavior and the only way I've found to shut up the warning is to add an explicit initialization. Signed-off-by: Arnd Bergmann <[email protected]> --- mm/memcontrol.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d06cae2de783..9340eb981653 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4762,6 +4762,7 @@ static int mem_cgroup_can_attach(struct cgroup_taskset *tset) * multiple. */ p = NULL; + memcg = NULL; cgroup_taskset_for_each_leader(leader, css, tset) { WARN_ON_ONCE(p); p = leader; -- 2.7.0
