Commit c58f0e84 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Greg Kroah-Hartman

sched/core: Handle overflow in cpu_shares_write_u64

[ Upstream commit 5b61d50a ]

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: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/155125501891.293431.3345233332801109696.stgit@buzzSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 5e4ea98f
...@@ -8512,6 +8512,8 @@ static void cpu_cgroup_attach(struct cgroup_taskset *tset) ...@@ -8512,6 +8512,8 @@ static void cpu_cgroup_attach(struct cgroup_taskset *tset)
static int cpu_shares_write_u64(struct cgroup_subsys_state *css, static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
struct cftype *cftype, u64 shareval) 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)); return sched_group_set_shares(css_tg(css), scale_load(shareval));
} }
......
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