proc/sysctl: add shared variables for range check

In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range.  This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

    $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
    248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

    # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
    add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
    Data                                         old     new   delta
    sysctl_vals                                    -      12     +12
    __kstrtab_sysctl_vals                          -      12     +12
    max                                           14      10      -4
    int_max                                       16       -     -16
    one                                           68       -     -68
    zero                                         128      28    -100
    Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
  Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
  Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 100 insertions, 106 deletions

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 6d726cef241c..a6a79f85c81a 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -291,14 +291,13 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
 }
 
 extern int pid_max;
-static int zero = 0;
 static struct ctl_table pid_ns_ctl_table[] = {
 	{
 		.procname = "ns_last_pid",
 		.maxlen = sizeof(int),
 		.mode = 0666, /* permissions are checked in the handler */
 		.proc_handler = pid_ns_ctl_handler,
-		.extra1 = &zero,
+		.extra1 = SYSCTL_ZERO,
 		.extra2 = &pid_max,
 	},
 	{ }
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 43186ccfa139..078950d9605b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -125,9 +125,6 @@ static int sixty = 60;
 #endif
 
 static int __maybe_unused neg_one = -1;
-
-static int zero;
-static int __maybe_unused one = 1;
 static int __maybe_unused two = 2;
 static int __maybe_unused four = 4;
 static unsigned long zero_ul;
@@ -385,8 +382,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= sysctl_schedstats,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif /* CONFIG_SCHEDSTATS */
 #endif /* CONFIG_SMP */
@@ -418,7 +415,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "numa_balancing",
@@ -426,8 +423,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= sysctl_numa_balancing,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif /* CONFIG_NUMA_BALANCING */
 #endif /* CONFIG_SCHED_DEBUG */
@@ -475,8 +472,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_CFS_BANDWIDTH
@@ -486,7 +483,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 	},
 #endif
 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
@@ -496,8 +493,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= sched_energy_aware_handler,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_PROVE_LOCKING
@@ -562,7 +559,7 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &neg_one,
-		.extra2		= &one,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_LATENCYTOP
@@ -696,8 +693,8 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		/* only handle a transition from default "0" to "1" */
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_MODULES
@@ -715,8 +712,8 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		/* only handle a transition from default "0" to "1" */
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_UEVENT_HELPER
@@ -875,7 +872,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &ten_thousand,
 	},
 	{
@@ -891,8 +888,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax_sysadmin,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "kptr_restrict",
@@ -900,7 +897,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax_sysadmin,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 #endif
@@ -925,8 +922,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler   = proc_watchdog,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "watchdog_thresh",
@@ -934,7 +931,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_watchdog_thresh,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &sixty,
 	},
 	{
@@ -943,8 +940,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
 		.proc_handler   = proc_nmi_watchdog,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "watchdog_cpumask",
@@ -960,8 +957,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler   = proc_soft_watchdog,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "softlockup_panic",
@@ -969,8 +966,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #ifdef CONFIG_SMP
 	{
@@ -979,8 +976,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif /* CONFIG_SMP */
 #endif
@@ -991,8 +988,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #ifdef CONFIG_SMP
 	{
@@ -1001,8 +998,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif /* CONFIG_SMP */
 #endif
@@ -1115,8 +1112,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "hung_task_check_count",
@@ -1124,7 +1121,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "hung_task_timeout_secs",
@@ -1201,7 +1198,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
 		.mode		= 0644,
 		.proc_handler	= perf_proc_update_handler,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "perf_cpu_time_max_percent",
@@ -1209,7 +1206,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(sysctl_perf_cpu_time_max_percent),
 		.mode		= 0644,
 		.proc_handler	= perf_cpu_time_max_percent_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},
 	{
@@ -1218,7 +1215,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(sysctl_perf_event_max_stack),
 		.mode		= 0644,
 		.proc_handler	= perf_event_max_stack_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &six_hundred_forty_kb,
 	},
 	{
@@ -1227,7 +1224,7 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(sysctl_perf_event_max_contexts_per_stack),
 		.mode		= 0644,
 		.proc_handler	= perf_event_max_stack_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_thousand,
 	},
 #endif
@@ -1237,8 +1234,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 	{
@@ -1247,8 +1244,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= timer_migration_handler,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_BPF_SYSCALL
@@ -1259,8 +1256,8 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		/* only handle a transition from default "0" to "1" */
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "bpf_stats_enabled",
@@ -1277,8 +1274,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
@@ -1288,8 +1285,8 @@ static struct ctl_table kern_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= stack_erasing_sysctl,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{ }
@@ -1302,7 +1299,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_overcommit_memory),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -1311,7 +1308,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_panic_on_oom),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -1348,7 +1345,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "dirty_background_ratio",
@@ -1356,7 +1353,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(dirty_background_ratio),
 		.mode		= 0644,
 		.proc_handler	= dirty_background_ratio_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},
 	{
@@ -1373,7 +1370,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(vm_dirty_ratio),
 		.mode		= 0644,
 		.proc_handler	= dirty_ratio_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},
 	{
@@ -1397,7 +1394,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(dirty_expire_interval),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "dirtytime_expire_seconds",
@@ -1405,7 +1402,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(dirtytime_expire_interval),
 		.mode		= 0644,
 		.proc_handler	= dirtytime_interval_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "swappiness",
@@ -1413,7 +1410,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(vm_swappiness),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},
 #ifdef CONFIG_HUGETLB_PAGE
@@ -1438,8 +1435,8 @@ static struct ctl_table vm_table[] = {
 		.maxlen			= sizeof(int),
 		.mode			= 0644,
 		.proc_handler	= sysctl_vm_numa_stat_handler,
-		.extra1			= &zero,
-		.extra2			= &one,
+		.extra1			= SYSCTL_ZERO,
+		.extra2			= SYSCTL_ONE,
 	},
 #endif
 	 {
@@ -1470,7 +1467,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= drop_caches_sysctl_handler,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &four,
 	},
 #ifdef CONFIG_COMPACTION
@@ -1496,8 +1493,8 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 
 #endif /* CONFIG_COMPACTION */
@@ -1507,7 +1504,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(min_free_kbytes),
 		.mode		= 0644,
 		.proc_handler	= min_free_kbytes_sysctl_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "watermark_boost_factor",
@@ -1515,7 +1512,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(watermark_boost_factor),
 		.mode		= 0644,
 		.proc_handler	= watermark_boost_factor_sysctl_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "watermark_scale_factor",
@@ -1523,7 +1520,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(watermark_scale_factor),
 		.mode		= 0644,
 		.proc_handler	= watermark_scale_factor_sysctl_handler,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &one_thousand,
 	},
 	{
@@ -1532,7 +1529,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(percpu_pagelist_fraction),
 		.mode		= 0644,
 		.proc_handler	= percpu_pagelist_fraction_sysctl_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #ifdef CONFIG_MMU
 	{
@@ -1541,7 +1538,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_max_map_count),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #else
 	{
@@ -1550,7 +1547,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_nr_trim_pages),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #endif
 	{
@@ -1566,7 +1563,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(block_dump),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "vfs_cache_pressure",
@@ -1574,7 +1571,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 	{
@@ -1583,7 +1580,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_legacy_va_layout),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #endif
 #ifdef CONFIG_NUMA
@@ -1593,7 +1590,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(node_reclaim_mode),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "min_unmapped_ratio",
@@ -1601,7 +1598,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
 		.mode		= 0644,
 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},
 	{
@@ -1610,7 +1607,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_min_slab_ratio),
 		.mode		= 0644,
 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},
 #endif
@@ -1661,7 +1658,7 @@ static struct ctl_table vm_table[] = {
 #endif
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #endif
 #ifdef CONFIG_HIGHMEM
@@ -1671,8 +1668,8 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(vm_highmem_is_dirtyable),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 #ifdef CONFIG_MEMORY_FAILURE
@@ -1682,8 +1679,8 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "memory_failure_recovery",
@@ -1691,8 +1688,8 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{
@@ -1738,8 +1735,8 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(sysctl_unprivileged_userfaultfd),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{ }
@@ -1875,8 +1872,8 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "protected_hardlinks",
@@ -1884,8 +1881,8 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "protected_fifos",
@@ -1893,7 +1890,7 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -1902,7 +1899,7 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -1911,7 +1908,7 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax_coredump,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
@@ -1948,7 +1945,7 @@ static struct ctl_table fs_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 	},
 	{ }
 };
@@ -1970,8 +1967,8 @@ static struct ctl_table debug_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_kprobes_optimization_handler,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{ }
@@ -3395,8 +3392,8 @@ int proc_do_static_key(struct ctl_table *table, int write,
 		.data   = &val,
 		.maxlen = sizeof(val),
 		.mode   = table->mode,
-		.extra1 = &zero,
-		.extra2 = &one,
+		.extra1 = SYSCTL_ZERO,
+		.extra2 = SYSCTL_ONE,
 	};
 
 	if (write && !capable(CAP_SYS_ADMIN))
diff --git a/kernel/ucount.c b/kernel/ucount.c
index feb128c7b5d9..a53cc2b4179c 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -52,16 +52,14 @@ static struct ctl_table_root set_root = {
 	.permissions = set_permissions,
 };
 
-static int zero = 0;
-static int int_max = INT_MAX;
 #define UCOUNT_ENTRY(name)				\
 	{						\
 		.procname	= name,			\
 		.maxlen		= sizeof(int),		\
 		.mode		= 0644,			\
 		.proc_handler	= proc_dointvec_minmax,	\
-		.extra1		= &zero,		\
-		.extra2		= &int_max,		\
+		.extra1		= SYSCTL_ZERO,		\
+		.extra2		= SYSCTL_INT_MAX,	\
 	}
 static struct ctl_table user_table[] = {
 	UCOUNT_ENTRY("max_user_namespaces"),