| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 127/241] sched/core: Handle overflow in cpu_shares_write_u64 | Date | Sun, 9 Jun 2019 18:41:09 +0200 |
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[ 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@yandex-team.ru> Acked-by: Peter 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@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- kernel/sched/core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1ef2fb4bbd6bd..0e70bfeded7fd 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8361,6 +8361,8 @@ 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
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