[ Upstream commit 5b61d50ab4ef590f5e1d4df15cd2cea5f5715308 ] Bit shift in scale_load() could overflow shares. This patch saturates it to MAX_SHARES like following sched_group_set_shares(). Example: # echo 9223372036854776832 > cpu.shares # cat cpu.shares Before patch: 1024 After pattch: 262144 Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/155125501891.293431.3345233332801109696.stgit@buzz Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- kernel/sched/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4617ede80f020..3861dd6da91e7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8512,6 +8512,8 @@ static void cpu_cgroup_attach(struct cgroup_taskset *tset) static int cpu_shares_write_u64(struct cgroup_subsys_state *css, struct cftype *cftype, u64 shareval) { + if (shareval > scale_load_down(ULONG_MAX)) + shareval = MAX_SHARES; return sched_group_set_shares(css_tg(css), scale_load(shareval)); } -- 2.20.1
