Commit-ID: 5b61d50ab4ef590f5e1d4df15cd2cea5f5715308 Gitweb: https://git.kernel.org/tip/5b61d50ab4ef590f5e1d4df15cd2cea5f5715308 Author: Konstantin Khlebnikov <khlebni...@yandex-team.ru> AuthorDate: Wed, 27 Feb 2019 11:10:18 +0300 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 19 Apr 2019 13:42:10 +0200
sched/core: Handle overflow in cpu_shares_write_u64 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 <khlebni...@yandex-team.ru> Acked-by: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/155125501891.293431.3345233332801109696.stgit@buzz Signed-off-by: Ingo Molnar <mi...@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 fb09eaad1d3a..685b1541ce51 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6507,6 +6507,8 @@ 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)); }
