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| author |   Mel Gorman <mgorman@techsingularity.net> | 2021-09-27 12:46:35 +0100 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2021-10-01 13:57:57 +0200 |
| commit | 703066188f63d66cc6b9d678e5b5ef1213c5938e (patch) | |
| tree | 28aece1cc7321f64178cc175a92a47ecc27833c7 | |
| parent | sched/fair: Add ancestors of unthrottled undecayed cfs_rq (diff) | |
| download | linux-dev-703066188f63d66cc6b9d678e5b5ef1213c5938e.tar.xz linux-dev-703066188f63d66cc6b9d678e5b5ef1213c5938e.zip | |
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
| -rw-r--r-- | kernel/sched/debug.c | 8 |
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; |