[Devel] [PATCH vz10] sched: enforce the 0..1 bound on sched_cpulimit_scale_cpufreq

[Konstantin Khorenko <khorenko@virtuozzo.com>]

The sched_cpulimit_scale_cpufreq sysctl was registered with
  .extra1 = SYSCTL_ZERO
  .extra2 = SYSCTL_ONE
but with .proc_handler = proc_dointvec.

proc_dointvec() ignores extra1/extra2, so the intended [0, 1] clamp was
never applied. sysctl_sched_cpulimit_scale_cpufreq is also unsigned int,
so proc_dointvec() is the wrong signedness for it in the first place.

Use proc_douintvec_minmax() so the already-declared bounds are honoured
and an out-of-range write is rejected.

Fixes: 4e99efb641da0 ("sched: Port CONFIG_CFS_CPULIMIT feature")
Feature: sched: ability to limit number of CPUs available to a CT
https://virtuozzo.atlassian.net/browse/VSTOR-137234
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d5b4d8c97a0c7..7580067e7f44a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4753,7 +4753,7 @@ static struct ctl_table sched_core_sysctls[] = {
 		.data		= &sysctl_sched_cpulimit_scale_cpufreq,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_douintvec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-- 
2.43.0