* [PATCH v2] hung_task: change sysctl_hung_task_check_count to int
@ 2013-09-23 8:43 Li Zefan
2013-09-23 13:37 ` [tip:core/locking] hung_task: Change sysctl_hung_task_check_count to 'int' tip-bot for Li Zefan
0 siblings, 1 reply; 2+ messages in thread
From: Li Zefan @ 2013-09-23 8:43 UTC (permalink / raw)
To: Andrew Morton; +Cc: Ingo Molnar, LKML
As sysctl_hung_task_check_count is unsigned long, when this value is
assigned to max_count in check_hung_uninterruptible_tasks(), it's
truncated to int type.
Therefore if we write 2^32 to sysctl.hung_task_check_count, hung task
detection will be effectively disabled.
With this fix, it will still truncate the user input, but reading
sysctl.hung_task_check_count reflects the truncated value.
v2: limit lowest value to 0.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched/sysctl.h | 2 +-
kernel/hung_task.c | 2 +-
kernel/sysctl.c | 5 +++--
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index bf8086b..9552afa 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -2,8 +2,8 @@
#define _SCHED_SYSCTL_H
#ifdef CONFIG_DETECT_HUNG_TASK
+extern int sysctl_hung_task_check_count;
extern unsigned int sysctl_hung_task_panic;
-extern unsigned long sysctl_hung_task_check_count;
extern unsigned long sysctl_hung_task_timeout_secs;
extern unsigned long sysctl_hung_task_warnings;
extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 3e97fb1..0422523 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -20,7 +20,7 @@
/*
* The number of tasks checked:
*/
-unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
+int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
/*
* Limit number of tasks checked in a batch.
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 7453418..bcb35ab 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -962,9 +962,10 @@ static struct ctl_table kern_table[] = {
{
.procname = "hung_task_check_count",
.data = &sysctl_hung_task_check_count,
- .maxlen = sizeof(unsigned long),
+ .maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_doulongvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
},
{
.procname = "hung_task_timeout_secs",
--
1.8.0.2
^ permalink raw reply related [flat|nested] 2+ messages in thread* [tip:core/locking] hung_task: Change sysctl_hung_task_check_count to 'int'
2013-09-23 8:43 [PATCH v2] hung_task: change sysctl_hung_task_check_count to int Li Zefan
@ 2013-09-23 13:37 ` tip-bot for Li Zefan
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Li Zefan @ 2013-09-23 13:37 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, tglx, lizefan
Commit-ID: cd64647f043e3fd3569bcf068f47f030198ff93a
Gitweb: http://git.kernel.org/tip/cd64647f043e3fd3569bcf068f47f030198ff93a
Author: Li Zefan <lizefan@huawei.com>
AuthorDate: Mon, 23 Sep 2013 16:43:58 +0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 23 Sep 2013 11:10:49 +0200
hung_task: Change sysctl_hung_task_check_count to 'int'
As 'sysctl_hung_task_check_count' is 'unsigned long' when this
value is assigned to max_count in check_hung_uninterruptible_tasks(),
it's truncated to 'int' type.
This causes a minor artifact: if we write 2^32 to sysctl.hung_task_check_count,
hung task detection will be effectively disabled.
With this fix, it will still truncate the user input to 32 bits, but
reading sysctl.hung_task_check_count reflects the actual truncated value.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/523FFF4E.9050401@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched/sysctl.h | 2 +-
kernel/hung_task.c | 2 +-
kernel/sysctl.c | 5 +++--
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index bf8086b..9552afa 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -2,8 +2,8 @@
#define _SCHED_SYSCTL_H
#ifdef CONFIG_DETECT_HUNG_TASK
+extern int sysctl_hung_task_check_count;
extern unsigned int sysctl_hung_task_panic;
-extern unsigned long sysctl_hung_task_check_count;
extern unsigned long sysctl_hung_task_timeout_secs;
extern unsigned long sysctl_hung_task_warnings;
extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 3e97fb1..0422523 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -20,7 +20,7 @@
/*
* The number of tasks checked:
*/
-unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
+int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
/*
* Limit number of tasks checked in a batch.
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b2f06f3..b24ed7f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -962,9 +962,10 @@ static struct ctl_table kern_table[] = {
{
.procname = "hung_task_check_count",
.data = &sysctl_hung_task_check_count,
- .maxlen = sizeof(unsigned long),
+ .maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_doulongvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
},
{
.procname = "hung_task_timeout_secs",
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2013-09-23 13:38 UTC | newest]
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2013-09-23 8:43 [PATCH v2] hung_task: change sysctl_hung_task_check_count to int Li Zefan
2013-09-23 13:37 ` [tip:core/locking] hung_task: Change sysctl_hung_task_check_count to 'int' tip-bot for Li Zefan
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