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authorMel Gorman <mgorman@techsingularity.net>2021-09-27 14:46:35 +0300
committerPeter Zijlstra <peterz@infradead.org>2021-10-01 14:57:57 +0300
commit703066188f63d66cc6b9d678e5b5ef1213c5938e (patch)
tree28aece1cc7321f64178cc175a92a47ecc27833c7 /kernel
parent2630cde26711dab0d0b56a8be1616475be646d13 (diff)
downloadlinux-703066188f63d66cc6b9d678e5b5ef1213c5938e.tar.xz
sched/fair: Null terminate buffer when updating tunable_scaling
This patch null-terminates the temporary buffer in sched_scaling_write() so kstrtouint() does not return failure and checks the value is valid. Before: $ cat /sys/kernel/debug/sched/tunable_scaling 1 $ echo 0 > /sys/kernel/debug/sched/tunable_scaling -bash: echo: write error: Invalid argument $ cat /sys/kernel/debug/sched/tunable_scaling 1 After: $ cat /sys/kernel/debug/sched/tunable_scaling 1 $ echo 0 > /sys/kernel/debug/sched/tunable_scaling $ cat /sys/kernel/debug/sched/tunable_scaling 0 $ echo 3 > /sys/kernel/debug/sched/tunable_scaling -bash: echo: write error: Invalid argument Fixes: 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20210927114635.GH3959@techsingularity.net
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/debug.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 49716228efb4..17a653b67006 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -173,16 +173,22 @@ static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[16];
+ unsigned int scaling;
if (cnt > 15)
cnt = 15;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
+ buf[cnt] = '\0';
- if (kstrtouint(buf, 10, &sysctl_sched_tunable_scaling))
+ if (kstrtouint(buf, 10, &scaling))
return -EINVAL;
+ if (scaling >= SCHED_TUNABLESCALING_END)
+ return -EINVAL;
+
+ sysctl_sched_tunable_scaling = scaling;
if (sched_update_scaling())
return -EINVAL;