diff mbox series

[2/4] proc/sysctl: add shared variables -1

Message ID 1589517224-123928-3-git-send-email-nixiaoming@huawei.com (mailing list archive)
State New, archived
Headers show
Series Move the sysctl interface to the corresponding feature code file | expand

Commit Message

Xiaoming Ni May 15, 2020, 4:33 a.m. UTC
Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
used in both sysctl_writes_strict and hung_task_warnings.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
---
 fs/proc/proc_sysctl.c     | 2 +-
 include/linux/sysctl.h    | 1 +
 kernel/hung_task_sysctl.c | 3 +--
 kernel/sysctl.c           | 3 +--
 4 files changed, 4 insertions(+), 5 deletions(-)

Comments

Kees Cook May 15, 2020, 8:06 a.m. UTC | #1
On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
> Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
> used in both sysctl_writes_strict and hung_task_warnings.
> 
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> ---
>  fs/proc/proc_sysctl.c     | 2 +-
>  include/linux/sysctl.h    | 1 +
>  kernel/hung_task_sysctl.c | 3 +--
>  kernel/sysctl.c           | 3 +--

How about doing this refactoring in advance of the extraction patch?

>  4 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
> index b6f5d45..acae1fa 100644
> --- a/fs/proc/proc_sysctl.c
> +++ b/fs/proc/proc_sysctl.c
> @@ -23,7 +23,7 @@
>  static const struct inode_operations proc_sys_dir_operations;
>  
>  /* shared constants to be used in various sysctls */
> -const int sysctl_vals[] = { 0, 1, INT_MAX };
> +const int sysctl_vals[] = { 0, 1, INT_MAX, -1 };
>  EXPORT_SYMBOL(sysctl_vals);
>  
>  /* Support for permanently empty directories */
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index 02fa844..6d741d6 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -41,6 +41,7 @@
>  #define SYSCTL_ZERO	((void *)&sysctl_vals[0])
>  #define SYSCTL_ONE	((void *)&sysctl_vals[1])
>  #define SYSCTL_INT_MAX	((void *)&sysctl_vals[2])
> +#define SYSCTL_NEG_ONE	((void *)&sysctl_vals[3])

Nit: let's keep these value-ordered? i.e. -1, 0, 1, INT_MAX.
Xiaoming Ni May 15, 2020, 9:06 a.m. UTC | #2
On 2020/5/15 16:06, Kees Cook wrote:
> On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
>> Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
>> used in both sysctl_writes_strict and hung_task_warnings.
>>
>> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>> ---
>>   fs/proc/proc_sysctl.c     | 2 +-
>>   include/linux/sysctl.h    | 1 +
>>   kernel/hung_task_sysctl.c | 3 +--
>>   kernel/sysctl.c           | 3 +--
> 
> How about doing this refactoring in advance of the extraction patch?
Before  advance of the extraction patch, neg_one is only used in one 
file, does it seem to have no value for refactoring?


> 
>>   4 files changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
>> index b6f5d45..acae1fa 100644
>> --- a/fs/proc/proc_sysctl.c
>> +++ b/fs/proc/proc_sysctl.c
>> @@ -23,7 +23,7 @@
>>   static const struct inode_operations proc_sys_dir_operations;
>>   
>>   /* shared constants to be used in various sysctls */
>> -const int sysctl_vals[] = { 0, 1, INT_MAX };
>> +const int sysctl_vals[] = { 0, 1, INT_MAX, -1 };
>>   EXPORT_SYMBOL(sysctl_vals);
>>   
>>   /* Support for permanently empty directories */
>> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
>> index 02fa844..6d741d6 100644
>> --- a/include/linux/sysctl.h
>> +++ b/include/linux/sysctl.h
>> @@ -41,6 +41,7 @@
>>   #define SYSCTL_ZERO	((void *)&sysctl_vals[0])
>>   #define SYSCTL_ONE	((void *)&sysctl_vals[1])
>>   #define SYSCTL_INT_MAX	((void *)&sysctl_vals[2])
>> +#define SYSCTL_NEG_ONE	((void *)&sysctl_vals[3])
> 
> Nit: let's keep these value-ordered? i.e. -1, 0, 1, INT_MAX.
Thanks for guidance, your method is better

Thanks.
Xiaoming Ni
Kees Cook May 15, 2020, 4:05 p.m. UTC | #3
On Fri, May 15, 2020 at 05:06:28PM +0800, Xiaoming Ni wrote:
> On 2020/5/15 16:06, Kees Cook wrote:
> > On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
> > > Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
> > > used in both sysctl_writes_strict and hung_task_warnings.
> > > 
> > > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > > ---
> > >   fs/proc/proc_sysctl.c     | 2 +-
> > >   include/linux/sysctl.h    | 1 +
> > >   kernel/hung_task_sysctl.c | 3 +--
> > >   kernel/sysctl.c           | 3 +--
> > 
> > How about doing this refactoring in advance of the extraction patch?
> Before  advance of the extraction patch, neg_one is only used in one file,
> does it seem to have no value for refactoring?

I guess it doesn't matter much, but I think it's easier to review in the
sense that neg_one is first extracted and then later everything else is
moved.
Xiaoming Ni May 16, 2020, 2:32 a.m. UTC | #4
On 2020/5/16 0:05, Kees Cook wrote:
> On Fri, May 15, 2020 at 05:06:28PM +0800, Xiaoming Ni wrote:
>> On 2020/5/15 16:06, Kees Cook wrote:
>>> On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
>>>> Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
>>>> used in both sysctl_writes_strict and hung_task_warnings.
>>>>
>>>> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>>>> ---
>>>>    fs/proc/proc_sysctl.c     | 2 +-
>>>>    include/linux/sysctl.h    | 1 +
>>>>    kernel/hung_task_sysctl.c | 3 +--
>>>>    kernel/sysctl.c           | 3 +--
>>>
>>> How about doing this refactoring in advance of the extraction patch?
>> Before  advance of the extraction patch, neg_one is only used in one file,
>> does it seem to have no value for refactoring?
> 
> I guess it doesn't matter much, but I think it's easier to review in the
> sense that neg_one is first extracted and then later everything else is
> moved.
> 
Later, when more features sysctl interface is moved to the code file, 
there will be more variables that need to be extracted.
So should I only extract the neg_one variable here, or should I extract 
all the variables used by multiple features?

  fs/proc/proc_sysctl.c  |  2 +-
  include/linux/sysctl.h | 11 ++++++++---
  kernel/sysctl.c        | 37 ++++++++++++++++---------------------
  3 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b6f5d45..3f77e64 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -23,7 +23,7 @@
  static const struct inode_operations proc_sys_dir_operations;

  /* shared constants to be used in various sysctls */
-const int sysctl_vals[] = { 0, 1, INT_MAX };
+const int sysctl_vals[] = { -1, 0, 1, 2, 4, 100, 1000, INT_MAX };
  EXPORT_SYMBOL(sysctl_vals);

  /* Support for permanently empty directories */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 43f8ef9..bf97c30 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -38,9 +38,14 @@
  struct ctl_dir;

  /* Keep the same order as in fs/proc/proc_sysctl.c */
-#define SYSCTL_ZERO	((void *)&sysctl_vals[0])
-#define SYSCTL_ONE	((void *)&sysctl_vals[1])
-#define SYSCTL_INT_MAX	((void *)&sysctl_vals[2])
+#define SYSCTL_NEG_ONE	((void *)&sysctl_vals[0])
+#define SYSCTL_ZERO	((void *)&sysctl_vals[1])
+#define SYSCTL_ONE	((void *)&sysctl_vals[2])
+#define SYSCTL_TWO	((void *)&sysctl_vals[3])
+#define SYSCTL_FOUR	((void *)&sysctl_vals[4])
+#define SYSCTL_ONE_HUNDRED	((void *)&sysctl_vals[5])
+#define SYSCTL_ONE_THOUSAND	((void *)&sysctl_vals[6])
+#define SYSCTL_INT_MAX	((void *)&sysctl_vals[7])

  extern const int sysctl_vals[];

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5dd6d01..efe6172 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -118,14 +118,9 @@

  /* Constants used for minimum and  maximum */

-static int __maybe_unused neg_one = -1;
-static int __maybe_unused two = 2;
-static int __maybe_unused four = 4;
  static unsigned long zero_ul;
  static unsigned long one_ul = 1;
  static unsigned long long_max = LONG_MAX;
-static int one_hundred = 100;
-static int one_thousand = 1000;
  #ifdef CONFIG_PRINTK
  static int ten_thousand = 10000;
  #endif
@@ -534,7 +529,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &neg_one,
+		.extra1		= SYSCTL_NEG_ONE,
  		.extra2		= SYSCTL_ONE,
  	},
  #endif
@@ -865,7 +860,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax_sysadmin,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
  	},
  #endif
  	{
@@ -1043,7 +1038,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= perf_cpu_time_max_percent_handler,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
  	},
  	{
  		.procname	= "perf_event_max_stack",
@@ -1061,7 +1056,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= perf_event_max_stack_handler,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_thousand,
+		.extra2		= SYSCTL_ONE_THOUSAND,
  	},
  #endif
  	{
@@ -1136,7 +1131,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
  	},
  	{
  		.procname	= "panic_on_oom",
@@ -1145,7 +1140,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
  	},
  	{
  		.procname	= "oom_kill_allocating_task",
@@ -1190,7 +1185,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= dirty_background_ratio_handler,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
  	},
  	{
  		.procname	= "dirty_background_bytes",
@@ -1207,7 +1202,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= dirty_ratio_handler,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
  	},
  	{
  		.procname	= "dirty_bytes",
@@ -1247,7 +1242,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
  	},
  #ifdef CONFIG_HUGETLB_PAGE
  	{
@@ -1304,7 +1299,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0200,
  		.proc_handler	= drop_caches_sysctl_handler,
  		.extra1		= SYSCTL_ONE,
-		.extra2		= &four,
+		.extra2		= SYSCTL_FOUR,
  	},
  #ifdef CONFIG_COMPACTION
  	{
@@ -1357,7 +1352,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= watermark_scale_factor_sysctl_handler,
  		.extra1		= SYSCTL_ONE,
-		.extra2		= &one_thousand,
+		.extra2		= SYSCTL_ONE_THOUSAND,
  	},
  	{
  		.procname	= "percpu_pagelist_fraction",
@@ -1436,7 +1431,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
  	},
  	{
  		.procname	= "min_slab_ratio",
@@ -1445,7 +1440,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &one_hundred,
+		.extra2		= SYSCTL_ONE_HUNDRED,
  	},
  #endif
  #ifdef CONFIG_SMP
@@ -1728,7 +1723,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0600,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
  	},
  	{
  		.procname	= "protected_regular",
@@ -1737,7 +1732,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0600,
  		.proc_handler	= proc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
  	},
  	{
  		.procname	= "suid_dumpable",
@@ -1746,7 +1741,7 @@ static int sysrq_sysctl_handler(struct ctl_table 
*table, int write,
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_minmax_coredump,
  		.extra1		= SYSCTL_ZERO,
-		.extra2		= &two,
+		.extra2		= SYSCTL_TWO,
  	},
  #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
  	{
Kees Cook May 16, 2020, 2:47 a.m. UTC | #5
On Sat, May 16, 2020 at 10:32:19AM +0800, Xiaoming Ni wrote:
> On 2020/5/16 0:05, Kees Cook wrote:
> > On Fri, May 15, 2020 at 05:06:28PM +0800, Xiaoming Ni wrote:
> > > On 2020/5/15 16:06, Kees Cook wrote:
> > > > On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
> > > > > Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
> > > > > used in both sysctl_writes_strict and hung_task_warnings.
> > > > > 
> > > > > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > > > > ---
> > > > >    fs/proc/proc_sysctl.c     | 2 +-
> > > > >    include/linux/sysctl.h    | 1 +
> > > > >    kernel/hung_task_sysctl.c | 3 +--
> > > > >    kernel/sysctl.c           | 3 +--
> > > > 
> > > > How about doing this refactoring in advance of the extraction patch?
> > > Before  advance of the extraction patch, neg_one is only used in one file,
> > > does it seem to have no value for refactoring?
> > 
> > I guess it doesn't matter much, but I think it's easier to review in the
> > sense that neg_one is first extracted and then later everything else is
> > moved.
> > 
> Later, when more features sysctl interface is moved to the code file, there
> will be more variables that need to be extracted.
> So should I only extract the neg_one variable here, or should I extract all
> the variables used by multiple features?

Hmm -- if you're going to do a consolidation pass, then nevermind, I
don't think order will matter then.

Thank you for the cleanup! Sorry we're giving you back-and-forth advice!

-Kees
Xiaoming Ni May 16, 2020, 3:05 a.m. UTC | #6
On 2020/5/16 10:47, Kees Cook wrote:
> On Sat, May 16, 2020 at 10:32:19AM +0800, Xiaoming Ni wrote:
>> On 2020/5/16 0:05, Kees Cook wrote:
>>> On Fri, May 15, 2020 at 05:06:28PM +0800, Xiaoming Ni wrote:
>>>> On 2020/5/15 16:06, Kees Cook wrote:
>>>>> On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
>>>>>> Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
>>>>>> used in both sysctl_writes_strict and hung_task_warnings.
>>>>>>
>>>>>> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>>>>>> ---
>>>>>>     fs/proc/proc_sysctl.c     | 2 +-
>>>>>>     include/linux/sysctl.h    | 1 +
>>>>>>     kernel/hung_task_sysctl.c | 3 +--
>>>>>>     kernel/sysctl.c           | 3 +--
>>>>>
>>>>> How about doing this refactoring in advance of the extraction patch?
>>>> Before  advance of the extraction patch, neg_one is only used in one file,
>>>> does it seem to have no value for refactoring?
>>>
>>> I guess it doesn't matter much, but I think it's easier to review in the
>>> sense that neg_one is first extracted and then later everything else is
>>> moved.
>>>
>> Later, when more features sysctl interface is moved to the code file, there
>> will be more variables that need to be extracted.
>> So should I only extract the neg_one variable here, or should I extract all
>> the variables used by multiple features?
> 
> Hmm -- if you're going to do a consolidation pass, then nevermind, I
> don't think order will matter then.
> 
> Thank you for the cleanup! Sorry we're giving you back-and-forth advice!
> 
> -Kees
> 

Sorry, I don't fully understand.
Does this mean that there is no need to adjust the patch order or the 
order of variables in sysctl_vals?
Should I extract only SYSCTL_NEG_ONE or should I extract all variables?

Thanks
Xiaoming Ni
Kees Cook May 17, 2020, 2:38 a.m. UTC | #7
On Sat, May 16, 2020 at 11:05:53AM +0800, Xiaoming Ni wrote:
> On 2020/5/16 10:47, Kees Cook wrote:
> > On Sat, May 16, 2020 at 10:32:19AM +0800, Xiaoming Ni wrote:
> > > On 2020/5/16 0:05, Kees Cook wrote:
> > > > On Fri, May 15, 2020 at 05:06:28PM +0800, Xiaoming Ni wrote:
> > > > > On 2020/5/15 16:06, Kees Cook wrote:
> > > > > > On Fri, May 15, 2020 at 12:33:42PM +0800, Xiaoming Ni wrote:
> > > > > > > Add the shared variable SYSCTL_NEG_ONE to replace the variable neg_one
> > > > > > > used in both sysctl_writes_strict and hung_task_warnings.
> > > > > > > 
> > > > > > > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > > > > > > ---
> > > > > > >     fs/proc/proc_sysctl.c     | 2 +-
> > > > > > >     include/linux/sysctl.h    | 1 +
> > > > > > >     kernel/hung_task_sysctl.c | 3 +--
> > > > > > >     kernel/sysctl.c           | 3 +--
> > > > > > 
> > > > > > How about doing this refactoring in advance of the extraction patch?
> > > > > Before  advance of the extraction patch, neg_one is only used in one file,
> > > > > does it seem to have no value for refactoring?
> > > > 
> > > > I guess it doesn't matter much, but I think it's easier to review in the
> > > > sense that neg_one is first extracted and then later everything else is
> > > > moved.
> > > > 
> > > Later, when more features sysctl interface is moved to the code file, there
> > > will be more variables that need to be extracted.
> > > So should I only extract the neg_one variable here, or should I extract all
> > > the variables used by multiple features?
> > 
> > Hmm -- if you're going to do a consolidation pass, then nevermind, I
> > don't think order will matter then.
> > 
> > Thank you for the cleanup! Sorry we're giving you back-and-forth advice!
> > 
> > -Kees
> > 
> 
> Sorry, I don't fully understand.
> Does this mean that there is no need to adjust the patch order or the order
> of variables in sysctl_vals?
> Should I extract only SYSCTL_NEG_ONE or should I extract all variables?

I think either order is fine -- I though you were only doing 1 variable.
If you're don't a bunch, then I don't think order is important.
diff mbox series

Patch

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b6f5d45..acae1fa 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -23,7 +23,7 @@ 
 static const struct inode_operations proc_sys_dir_operations;
 
 /* shared constants to be used in various sysctls */
-const int sysctl_vals[] = { 0, 1, INT_MAX };
+const int sysctl_vals[] = { 0, 1, INT_MAX, -1 };
 EXPORT_SYMBOL(sysctl_vals);
 
 /* Support for permanently empty directories */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 02fa844..6d741d6 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -41,6 +41,7 @@ 
 #define SYSCTL_ZERO	((void *)&sysctl_vals[0])
 #define SYSCTL_ONE	((void *)&sysctl_vals[1])
 #define SYSCTL_INT_MAX	((void *)&sysctl_vals[2])
+#define SYSCTL_NEG_ONE	((void *)&sysctl_vals[3])
 
 extern const int sysctl_vals[];
 
diff --git a/kernel/hung_task_sysctl.c b/kernel/hung_task_sysctl.c
index 5b10d4e..62a51f5 100644
--- a/kernel/hung_task_sysctl.c
+++ b/kernel/hung_task_sysctl.c
@@ -14,7 +14,6 @@ 
  * and hung_task_check_interval_secs
  */
 static unsigned long hung_task_timeout_max = (LONG_MAX / HZ);
-static int neg_one = -1;
 static struct ctl_table hung_task_sysctls[] = {
 	{
 		.procname	= "hung_task_panic",
@@ -55,7 +54,7 @@ 
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &neg_one,
+		.extra1		= SYSCTL_NEG_ONE,
 	},
 	{}
 };
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 20adae0..01fc559 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -124,7 +124,6 @@ 
 static int sixty = 60;
 #endif
 
-static int __maybe_unused neg_one = -1;
 static int __maybe_unused two = 2;
 static int __maybe_unused four = 4;
 static unsigned long zero_ul;
@@ -540,7 +539,7 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &neg_one,
+		.extra1		= SYSCTL_NEG_ONE,
 		.extra2		= SYSCTL_ONE,
 	},
 #endif