[PATCH 4.4 01/56] perf/core: Fix the perf_cpu_time_max_percent check

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tan Xiaojun <tanxiaojun@xxxxxxxxxx>

commit 1572e45a924f254d9570093abde46430c3172e3d upstream.

Use "proc_dointvec_minmax" instead of "proc_dointvec" to check the input
value from user-space.

If not, we can set a big value and some vars will overflow like
"sysctl_perf_event_sample_rate" which will cause a lot of unexpected
problems.

Signed-off-by: Tan Xiaojun <tanxiaojun@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: <acme@xxxxxxxxxx>
Cc: <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1487829879-56237-1-git-send-email-tanxiaojun@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/events/core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -229,7 +229,7 @@ int perf_cpu_time_max_percent_handler(st
 				void __user *buffer, size_t *lenp,
 				loff_t *ppos)
 {
-	int ret = proc_dointvec(table, write, buffer, lenp, ppos);
+	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 
 	if (ret || !write)
 		return ret;