This is a note to let you know that I've just added the patch titled
perf: Enforce 1 as lower limit for perf_event_max_sample_rate
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-enforce-1-as-lower-limit-for-perf_event_max_sample_rate.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 723478c8a471403c53cf144999701f6e0c4bbd11 Mon Sep 17 00:00:00 2001
From: Knut Petersen <Knut_Petersen@xxxxxxxxxxx>
Date: Wed, 25 Sep 2013 14:29:37 +0200
Subject: perf: Enforce 1 as lower limit for perf_event_max_sample_rate
From: Knut Petersen <Knut_Petersen@xxxxxxxxxxx>
commit 723478c8a471403c53cf144999701f6e0c4bbd11 upstream.
/proc/sys/kernel/perf_event_max_sample_rate will accept
negative values as well as 0.
Negative values are unreasonable, and 0 causes a
divide by zero exception in perf_proc_update_handler.
This patch enforces a lower limit of 1.
Signed-off-by: Knut Petersen <Knut_Petersen@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/5242DB0C.4070005@xxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Weng Meiling <wengmeiling.weng@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 2 +-
kernel/sysctl.c | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -190,7 +190,7 @@ int perf_proc_update_handler(struct ctl_
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;
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1049,6 +1049,7 @@ static struct ctl_table kern_table[] = {
.maxlen = sizeof(sysctl_perf_event_sample_rate),
.mode = 0644,
.proc_handler = perf_proc_update_handler,
+ .extra1 = &one,
},
{
.procname = "perf_cpu_time_max_percent",
Patches currently in stable-queue which might be from Knut_Petersen@xxxxxxxxxxx are
queue-3.10/perf-enforce-1-as-lower-limit-for-perf_event_max_sample_rate.patch
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