Summary

* Move sysctls out of the kern_table array
 
   This is the final move of ctl_tables into their respective subsystems. Only 5
   (out of the original 50) will remain in kernel/sysctl.c file; these handle
   either sysctl or common arch variables.
 
   By decentralizing sysctl registrations, subsystem maintainers regain control
   over their sysctl interfaces, improving maintainability and reducing the
   likelihood of merge conflicts.
 
 * docs: Remove false positives from check-sysctl-docs
 
   Stopped falsely identifying sysctls as undocumented or unimplemented in the
   check-sysctl-docs script. This script can now be used to automatically
   identify if documentation is missing.
 
 * Testing
 
   All these have been in linux-next since rc3, giving them a solid 3 to 4 weeks
   worth of testing. Additionally, sysctl selftests and kunit were also run
   locally on my x86_64
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Merge tag 'sysctl-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl

Pull sysctl updates from Joel Granados:

 - Move sysctls out of the kern_table array

   This is the final move of ctl_tables into their respective
   subsystems. Only 5 (out of the original 50) will remain in
   kernel/sysctl.c file; these handle either sysctl or common arch
   variables.

   By decentralizing sysctl registrations, subsystem maintainers regain
   control over their sysctl interfaces, improving maintainability and
   reducing the likelihood of merge conflicts.

 - docs: Remove false positives from check-sysctl-docs

   Stopped falsely identifying sysctls as undocumented or unimplemented
   in the check-sysctl-docs script. This script can now be used to
   automatically identify if documentation is missing.

* tag 'sysctl-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: (23 commits)
  docs: Downgrade arm64 & riscv from titles to comment
  docs: Replace spaces with tabs in check-sysctl-docs
  docs: Remove colon from ctltable title in vm.rst
  docs: Add awk section for ucount sysctl entries
  docs: Use skiplist when checking sysctl admin-guide
  docs: nixify check-sysctl-docs
  sysctl: rename kern_table -> sysctl_subsys_table
  kernel/sys.c: Move overflow{uid,gid} sysctl into kernel/sys.c
  uevent: mv uevent_helper into kobject_uevent.c
  sysctl: Removed unused variable
  sysctl: Nixify sysctl.sh
  sysctl: Remove superfluous includes from kernel/sysctl.c
  sysctl: Remove (very) old file changelog
  sysctl: Move sysctl_panic_on_stackoverflow to kernel/panic.c
  sysctl: move cad_pid into kernel/pid.c
  sysctl: Move tainted ctl_table into kernel/panic.c
  Input: sysrq: mv sysrq into drivers/tty/sysrq.c
  fork: mv threads-max into kernel/fork.c
  parisc/power: Move soft-power into power.c
  mm: move randomize_va_space into memory.c
  ...

Documentation/admin-guide/sysctl/kernel.rst

@@ -1014,30 +1014,26 @@ perf_user_access (arm64 and riscv only)
 
 Controls user space access for reading perf event counters.
 
-arm64
+* for arm64
-=====
+  The default value is 0 (access disabled).
 
-The default value is 0 (access disabled).
+  When set to 1, user space can read performance monitor counter registers
+  directly.
 
-When set to 1, user space can read performance monitor counter registers
+  See Documentation/arch/arm64/perf.rst for more information.
-directly.
 
-See Documentation/arch/arm64/perf.rst for more information.
+* for riscv
+  When set to 0, user space access is disabled.
 
-riscv
+  The default value is 1, user space can read performance monitor counter
-=====
+  registers through perf, any direct access without perf intervention will trigger
+  an illegal instruction.
 
-When set to 0, user space access is disabled.
+  When set to 2, which enables legacy mode (user space has direct access to cycle
+  and insret CSRs only). Note that this legacy value is deprecated and will be
+  removed once all user space applications are fixed.
 
-The default value is 1, user space can read performance monitor counter
+  Note that the time CSR is always directly accessible to all modes.
-registers through perf, any direct access without perf intervention will trigger
-an illegal instruction.
-
-When set to 2, which enables legacy mode (user space has direct access to cycle
-and insret CSRs only). Note that this legacy value is deprecated and will be
-removed once all user space applications are fixed.
-
-Note that the time CSR is always directly accessible to all modes.
 
 pid_max
 =======

Documentation/admin-guide/sysctl/vm.rst

@@ -465,8 +465,8 @@ The minimum value is 1 (1/1 -> 100%). The value less than 1 completely
 disables protection of the pages.
 
 
-max_map_count:
+max_map_count
-==============
+=============
 
 This file contains the maximum number of memory map areas a process
 may have. Memory map areas are used as a side-effect of calling
@@ -495,8 +495,8 @@ memory allocations.
 The default value depends on CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT.
 
 
-memory_failure_early_kill:
+memory_failure_early_kill
-==========================
+=========================
 
 Control how to kill processes when uncorrected memory error (typically
 a 2bit error in a memory module) is detected in the background by hardware

drivers/parisc/power.c

@@ -83,7 +83,25 @@ static struct task_struct *power_task;
 #define SYSCTL_FILENAME	"sys/kernel/power"
 
 /* soft power switch enabled/disabled */
-int pwrsw_enabled __read_mostly = 1;
+static int pwrsw_enabled __read_mostly = 1;
+
+static const struct ctl_table power_sysctl_table[] = {
+	{
+		.procname	= "soft-power",
+		.data		= &pwrsw_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+};
+
+static int __init init_power_sysctl(void)
+{
+	register_sysctl_init("kernel", power_sysctl_table);
+	return 0;
+}
+
+arch_initcall(init_power_sysctl);
 
 /* main kernel thread worker. It polls the button state */
 static int kpowerswd(void *param)

drivers/tty/sysrq.c

@@ -1120,6 +1120,47 @@ int sysrq_toggle_support(int enable_mask)
 }
 EXPORT_SYMBOL_GPL(sysrq_toggle_support);
 
+static int sysrq_sysctl_handler(const struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int tmp, ret;
+	struct ctl_table t = *table;
+
+	tmp = sysrq_mask();
+	t.data = &tmp;
+
+	/*
+	 * Behaves like do_proc_dointvec as t does not have min nor max.
+	 */
+	ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+
+	if (ret || !write)
+		return ret;
+
+	if (write)
+		sysrq_toggle_support(tmp);
+
+	return 0;
+}
+
+static const struct ctl_table sysrq_sysctl_table[] = {
+	{
+		.procname	= "sysrq",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= sysrq_sysctl_handler,
+	},
+};
+
+static int __init init_sysrq_sysctl(void)
+{
+	register_sysctl_init("kernel", sysrq_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_sysrq_sysctl);
+
 static int __sysrq_swap_key_ops(u8 key, const struct sysrq_key_op *insert_op_p,
 				const struct sysrq_key_op *remove_op_p)
 {

include/linux/kmod.h

@@ -14,10 +14,7 @@
 #include <linux/workqueue.h>
 #include <linux/sysctl.h>
 
-#define KMOD_PATH_LEN 256
-
 #ifdef CONFIG_MODULES
-extern char modprobe_path[]; /* for sysctl */
 /* modprobe exit status on success, -ve on error.  Return value
  * usually useless though. */
 extern __printf(2, 3)

include/linux/module.h

@@ -304,7 +304,6 @@ struct notifier_block;
 
 #ifdef CONFIG_MODULES
 
-extern int modules_disabled; /* for sysctl */
 /* Get/put a kernel symbol (calls must be symmetric) */
 void *__symbol_get(const char *symbol);
 void *__symbol_get_gpl(const char *symbol);

include/linux/panic.h

@@ -25,8 +25,6 @@ extern int panic_on_warn;
 extern unsigned long panic_on_taint;
 extern bool panic_on_taint_nousertaint;
 
-extern int sysctl_panic_on_rcu_stall;
-extern int sysctl_max_rcu_stall_to_panic;
 extern int sysctl_panic_on_stackoverflow;
 
 extern bool crash_kexec_post_notifiers;

include/linux/rtmutex.h

@@ -18,7 +18,7 @@
 #include <linux/rbtree_types.h>
 #include <linux/spinlock_types_raw.h>
 
-extern int max_lock_depth; /* for sysctl */
+extern int max_lock_depth;
 
 struct rt_mutex_base {
 	raw_spinlock_t		wait_lock;

include/linux/sysctl.h

@@ -242,9 +242,7 @@ int do_proc_douintvec(const struct ctl_table *table, int write,
 				  int write, void *data),
 		      void *data);
 
-extern int pwrsw_enabled;
 extern int unaligned_enabled;
-extern int unaligned_dump_stack;
 extern int no_unaligned_warning;
 
 #else /* CONFIG_SYSCTL */
@@ -285,7 +283,4 @@ static inline bool sysctl_is_alias(char *param)
 }
 #endif /* CONFIG_SYSCTL */
 
-int sysctl_max_threads(const struct ctl_table *table, int write, void *buffer,
-		size_t *lenp, loff_t *ppos);
-
 #endif /* _LINUX_SYSCTL_H */

kernel/fork.c

@@ -3219,7 +3219,7 @@ int unshare_files(void)
 	return 0;
 }
 
-int sysctl_max_threads(const struct ctl_table *table, int write,
+static int sysctl_max_threads(const struct ctl_table *table, int write,
 		       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
@@ -3241,3 +3241,21 @@ int sysctl_max_threads(const struct ctl_table *table, int write,
 
 	return 0;
 }
+
+static const struct ctl_table fork_sysctl_table[] = {
+	{
+		.procname	= "threads-max",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= sysctl_max_threads,
+	},
+};
+
+static int __init init_fork_sysctl(void)
+{
+	register_sysctl_init("kernel", fork_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_fork_sysctl);

kernel/locking/rtmutex_api.c

@@ -13,6 +13,24 @@
  */
 int max_lock_depth = 1024;
 
+static const struct ctl_table rtmutex_sysctl_table[] = {
+	{
+		.procname	= "max_lock_depth",
+		.data		= &max_lock_depth,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+};
+
+static int __init init_rtmutex_sysctl(void)
+{
+	register_sysctl_init("kernel", rtmutex_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_rtmutex_sysctl);
+
 /*
  * Debug aware fast / slowpath lock,trylock,unlock
  *

kernel/module/internal.h

@@ -58,6 +58,9 @@ extern const struct kernel_symbol __stop___ksymtab_gpl[];
 extern const u32 __start___kcrctab[];
 extern const u32 __start___kcrctab_gpl[];
 
+#define KMOD_PATH_LEN 256
+extern char modprobe_path[];
+
 struct load_info {
 	const char *name;
 	/* pointer to module in temporary copy, freed at end of load_module() */

kernel/module/main.c

@@ -126,9 +126,37 @@ static void mod_update_bounds(struct module *mod)
 }
 
 /* Block module loading/unloading? */
-int modules_disabled;
+static int modules_disabled;
 core_param(nomodule, modules_disabled, bint, 0);
 
+static const struct ctl_table module_sysctl_table[] = {
+	{
+		.procname	= "modprobe",
+		.data		= &modprobe_path,
+		.maxlen		= KMOD_PATH_LEN,
+		.mode		= 0644,
+		.proc_handler	= proc_dostring,
+	},
+	{
+		.procname	= "modules_disabled",
+		.data		= &modules_disabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		/* only handle a transition from default "0" to "1" */
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
+	},
+};
+
+static int __init init_module_sysctl(void)
+{
+	register_sysctl_init("kernel", module_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_module_sysctl);
+
 /* Waiting for a module to finish initializing? */
 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
 

kernel/panic.c

@@ -84,6 +84,50 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
 EXPORT_SYMBOL(panic_notifier_list);
 
 #ifdef CONFIG_SYSCTL
+
+/*
+ * Taint values can only be increased
+ * This means we can safely use a temporary.
+ */
+static int proc_taint(const struct ctl_table *table, int write,
+			       void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	unsigned long tmptaint = get_taint();
+	int err;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &tmptaint;
+	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+
+	if (write) {
+		int i;
+
+		/*
+		 * If we are relying on panic_on_taint not producing
+		 * false positives due to userspace input, bail out
+		 * before setting the requested taint flags.
+		 */
+		if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
+			return -EINVAL;
+
+		/*
+		 * Poor man's atomic or. Not worth adding a primitive
+		 * to everyone's atomic.h for this
+		 */
+		for (i = 0; i < TAINT_FLAGS_COUNT; i++)
+			if ((1UL << i) & tmptaint)
+				add_taint(i, LOCKDEP_STILL_OK);
+	}
+
+	return err;
+}
+
 static const struct ctl_table kern_panic_table[] = {
 #ifdef CONFIG_SMP
 	{
@@ -96,6 +140,12 @@ static const struct ctl_table kern_panic_table[] = {
 		.extra2         = SYSCTL_ONE,
 	},
 #endif
+	{
+		.procname	= "tainted",
+		.maxlen		= sizeof(long),
+		.mode		= 0644,
+		.proc_handler	= proc_taint,
+	},
 	{
 		.procname	= "panic",
 		.data		= &panic_timeout,
@@ -133,6 +183,16 @@ static const struct ctl_table kern_panic_table[] = {
 		.mode           = 0644,
 		.proc_handler   = proc_douintvec,
 	},
+#if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
+	defined(CONFIG_DEBUG_STACKOVERFLOW)
+	{
+		.procname	= "panic_on_stackoverflow",
+		.data		= &sysctl_panic_on_stackoverflow,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
 };
 
 static __init int kernel_panic_sysctls_init(void)

kernel/pid.c

@@ -713,6 +713,29 @@ static struct ctl_table_root pid_table_root = {
 	.set_ownership	= pid_table_root_set_ownership,
 };
 
+static int proc_do_cad_pid(const struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	struct pid *new_pid;
+	pid_t tmp_pid;
+	int r;
+	struct ctl_table tmp_table = *table;
+
+	tmp_pid = pid_vnr(cad_pid);
+	tmp_table.data = &tmp_pid;
+
+	r = proc_dointvec(&tmp_table, write, buffer, lenp, ppos);
+	if (r || !write)
+		return r;
+
+	new_pid = find_get_pid(tmp_pid);
+	if (!new_pid)
+		return -ESRCH;
+
+	put_pid(xchg(&cad_pid, new_pid));
+	return 0;
+}
+
 static const struct ctl_table pid_table[] = {
 	{
 		.procname	= "pid_max",
@@ -723,6 +746,14 @@ static const struct ctl_table pid_table[] = {
 		.extra1		= &pid_max_min,
 		.extra2		= &pid_max_max,
 	},
+#ifdef CONFIG_PROC_SYSCTL
+	{
+		.procname	= "cad_pid",
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= proc_do_cad_pid,
+	},
+#endif
 };
 #endif
 

kernel/rcu/tree_stall.h

@@ -17,8 +17,37 @@
 // Controlling CPU stall warnings, including delay calculation.
 
 /* panic() on RCU Stall sysctl. */
-int sysctl_panic_on_rcu_stall __read_mostly;
+static int sysctl_panic_on_rcu_stall __read_mostly;
-int sysctl_max_rcu_stall_to_panic __read_mostly;
+static int sysctl_max_rcu_stall_to_panic __read_mostly;
+
+static const struct ctl_table rcu_stall_sysctl_table[] = {
+	{
+		.procname	= "panic_on_rcu_stall",
+		.data		= &sysctl_panic_on_rcu_stall,
+		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "max_rcu_stall_to_panic",
+		.data		= &sysctl_max_rcu_stall_to_panic,
+		.maxlen		= sizeof(sysctl_max_rcu_stall_to_panic),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_INT_MAX,
+	},
+};
+
+static int __init init_rcu_stall_sysctl(void)
+{
+	register_sysctl_init("kernel", rcu_stall_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_rcu_stall_sysctl);
 
 #ifdef CONFIG_SYSFS
 

kernel/sys.c

@@ -181,6 +181,35 @@ int fs_overflowgid = DEFAULT_FS_OVERFLOWGID;
 EXPORT_SYMBOL(fs_overflowuid);
 EXPORT_SYMBOL(fs_overflowgid);
 
+static const struct ctl_table overflow_sysctl_table[] = {
+	{
+		.procname	= "overflowuid",
+		.data		= &overflowuid,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_MAXOLDUID,
+	},
+	{
+		.procname	= "overflowgid",
+		.data		= &overflowgid,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_MAXOLDUID,
+	},
+};
+
+static int __init init_overflow_sysctl(void)
+{
+	register_sysctl_init("kernel", overflow_sysctl_table);
+	return 0;
+}
+
+postcore_initcall(init_overflow_sysctl);
+
 /*
  * Returns true if current's euid is same as p's uid or euid,
  * or has CAP_SYS_NICE to p's user_ns.

kernel/sysctl.c

@@ -1,69 +1,28 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * sysctl.c: General linux system control interface
- *
- * Begun 24 March 1995, Stephen Tweedie
- * Added /proc support, Dec 1995
- * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
- * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
- * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
- * Dynamic registration fixes, Stephen Tweedie.
- * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
- * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
- *  Horn.
- * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
- * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
- * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
- *  Wendling.
- * The list_for_each() macro wasn't appropriate for the sysctl loop.
- *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
  */
 
-#include <linux/module.h>
 #include <linux/sysctl.h>
 #include <linux/bitmap.h>
-#include <linux/printk.h>
 #include <linux/proc_fs.h>
-#include <linux/security.h>
 #include <linux/ctype.h>
-#include <linux/filter.h>
-#include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/kobject.h>
-#include <linux/net.h>
-#include <linux/sysrq.h>
 #include <linux/highuid.h>
 #include <linux/writeback.h>
-#include <linux/ratelimit.h>
 #include <linux/initrd.h>
-#include <linux/key.h>
 #include <linux/times.h>
 #include <linux/limits.h>
 #include <linux/syscalls.h>
-#include <linux/nfs_fs.h>
-#include <linux/acpi.h>
-#include <linux/reboot.h>
-#include <linux/kmod.h>
 #include <linux/capability.h>
-#include <linux/binfmts.h>
-#include <linux/sched/sysctl.h>
-#include <linux/mount.h>
-#include <linux/pid.h>
 
 #include "../lib/kstrtox.h"
 
 #include <linux/uaccess.h>
 #include <asm/processor.h>
 
-#ifdef CONFIG_X86
-#include <asm/nmi.h>
-#include <asm/io.h>
-#endif
-#ifdef CONFIG_RT_MUTEXES
-#include <linux/rtmutex.h>
-#endif
-
 /* shared constants to be used in various sysctls */
 const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
 EXPORT_SYMBOL(sysctl_vals);
@@ -736,49 +695,6 @@ int proc_douintvec(const struct ctl_table *table, int write, void *buffer,
 				 do_proc_douintvec_conv, NULL);
 }
 
-/*
- * Taint values can only be increased
- * This means we can safely use a temporary.
- */
-static int proc_taint(const struct ctl_table *table, int write,
-			       void *buffer, size_t *lenp, loff_t *ppos)
-{
-	struct ctl_table t;
-	unsigned long tmptaint = get_taint();
-	int err;
-
-	if (write && !capable(CAP_SYS_ADMIN))
-		return -EPERM;
-
-	t = *table;
-	t.data = &tmptaint;
-	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
-	if (err < 0)
-		return err;
-
-	if (write) {
-		int i;
-
-		/*
-		 * If we are relying on panic_on_taint not producing
-		 * false positives due to userspace input, bail out
-		 * before setting the requested taint flags.
-		 */
-		if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
-			return -EINVAL;
-
-		/*
-		 * Poor man's atomic or. Not worth adding a primitive
-		 * to everyone's atomic.h for this
-		 */
-		for (i = 0; i < TAINT_FLAGS_COUNT; i++)
-			if ((1UL << i) & tmptaint)
-				add_taint(i, LOCKDEP_STILL_OK);
-	}
-
-	return err;
-}
-
 /**
  * struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
  * @min: pointer to minimum allowable value
@@ -968,26 +884,6 @@ int proc_dou8vec_minmax(const struct ctl_table *table, int write,
 }
 EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
 
-#ifdef CONFIG_MAGIC_SYSRQ
-static int sysrq_sysctl_handler(const struct ctl_table *table, int write,
-				void *buffer, size_t *lenp, loff_t *ppos)
-{
-	int tmp, ret;
-
-	tmp = sysrq_mask();
-
-	ret = __do_proc_dointvec(&tmp, table, write, buffer,
-			       lenp, ppos, NULL, NULL);
-	if (ret || !write)
-		return ret;
-
-	if (write)
-		sysrq_toggle_support(tmp);
-
-	return 0;
-}
-#endif
-
 static int __do_proc_doulongvec_minmax(void *data,
 		const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos,
@@ -1292,28 +1188,6 @@ int proc_dointvec_ms_jiffies(const struct ctl_table *table, int write, void *buf
 				do_proc_dointvec_ms_jiffies_conv, NULL);
 }
 
-static int proc_do_cad_pid(const struct ctl_table *table, int write, void *buffer,
-		size_t *lenp, loff_t *ppos)
-{
-	struct pid *new_pid;
-	pid_t tmp;
-	int r;
-
-	tmp = pid_vnr(cad_pid);
-
-	r = __do_proc_dointvec(&tmp, table, write, buffer,
-			       lenp, ppos, NULL, NULL);
-	if (r || !write)
-		return r;
-
-	new_pid = find_get_pid(tmp);
-	if (!new_pid)
-		return -ESRCH;
-
-	put_pid(xchg(&cad_pid, new_pid));
-	return 0;
-}
-
 /**
  * proc_do_large_bitmap - read/write from/to a large bitmap
  * @table: the sysctl table
@@ -1580,14 +1454,8 @@ int proc_do_static_key(const struct ctl_table *table, int write,
 	return ret;
 }
 
-static const struct ctl_table kern_table[] = {
+static const struct ctl_table sysctl_subsys_table[] = {
 #ifdef CONFIG_PROC_SYSCTL
-	{
-		.procname	= "tainted",
-		.maxlen 	= sizeof(long),
-		.mode		= 0644,
-		.proc_handler	= proc_taint,
-	},
 	{
 		.procname	= "sysctl_writes_strict",
 		.data		= &sysctl_writes_strict,
@@ -1598,95 +1466,6 @@ static const struct ctl_table kern_table[] = {
 		.extra2		= SYSCTL_ONE,
 	},
 #endif
-#ifdef CONFIG_PARISC
-	{
-		.procname	= "soft-power",
-		.data		= &pwrsw_enabled,
-		.maxlen		= sizeof (int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
-#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
-	{
-		.procname	= "unaligned-trap",
-		.data		= &unaligned_enabled,
-		.maxlen		= sizeof (int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
-#ifdef CONFIG_MODULES
-	{
-		.procname	= "modprobe",
-		.data		= &modprobe_path,
-		.maxlen		= KMOD_PATH_LEN,
-		.mode		= 0644,
-		.proc_handler	= proc_dostring,
-	},
-	{
-		.procname	= "modules_disabled",
-		.data		= &modules_disabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		/* only handle a transition from default "0" to "1" */
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE,
-		.extra2		= SYSCTL_ONE,
-	},
-#endif
-#ifdef CONFIG_UEVENT_HELPER
-	{
-		.procname	= "hotplug",
-		.data		= &uevent_helper,
-		.maxlen		= UEVENT_HELPER_PATH_LEN,
-		.mode		= 0644,
-		.proc_handler	= proc_dostring,
-	},
-#endif
-#ifdef CONFIG_MAGIC_SYSRQ
-	{
-		.procname	= "sysrq",
-		.data		= NULL,
-		.maxlen		= sizeof (int),
-		.mode		= 0644,
-		.proc_handler	= sysrq_sysctl_handler,
-	},
-#endif
-#ifdef CONFIG_PROC_SYSCTL
-	{
-		.procname	= "cad_pid",
-		.data		= NULL,
-		.maxlen		= sizeof (int),
-		.mode		= 0600,
-		.proc_handler	= proc_do_cad_pid,
-	},
-#endif
-	{
-		.procname	= "threads-max",
-		.data		= NULL,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= sysctl_max_threads,
-	},
-	{
-		.procname	= "overflowuid",
-		.data		= &overflowuid,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_MAXOLDUID,
-	},
-	{
-		.procname	= "overflowgid",
-		.data		= &overflowgid,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_MAXOLDUID,
-	},
 	{
 		.procname	= "ngroups_max",
 		.data		= (void *)&ngroups_max,
@@ -1701,20 +1480,10 @@ static const struct ctl_table kern_table[] = {
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec,
 	},
-#if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
-	defined(CONFIG_DEBUG_STACKOVERFLOW)
 	{
-		.procname	= "panic_on_stackoverflow",
+		.procname	= "unaligned-trap",
-		.data		= &sysctl_panic_on_stackoverflow,
+		.data		= &unaligned_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
-#if defined(CONFIG_MMU)
-	{
-		.procname	= "randomize_va_space",
-		.data		= &randomize_va_space,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
@@ -1729,40 +1498,11 @@ static const struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
-#ifdef CONFIG_RT_MUTEXES
-	{
-		.procname	= "max_lock_depth",
-		.data		= &max_lock_depth,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
-#ifdef CONFIG_TREE_RCU
-	{
-		.procname	= "panic_on_rcu_stall",
-		.data		= &sysctl_panic_on_rcu_stall,
-		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "max_rcu_stall_to_panic",
-		.data		= &sysctl_max_rcu_stall_to_panic,
-		.maxlen		= sizeof(sysctl_max_rcu_stall_to_panic),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE,
-		.extra2		= SYSCTL_INT_MAX,
-	},
-#endif
 };
 
 int __init sysctl_init_bases(void)
 {
-	register_sysctl_init("kernel", kern_table);
+	register_sysctl_init("kernel", sysctl_subsys_table);
 
 	return 0;
 }

lib/kobject_uevent.c

@@ -826,3 +826,23 @@ static int __init kobject_uevent_init(void)
 
 postcore_initcall(kobject_uevent_init);
 #endif
+
+#ifdef CONFIG_UEVENT_HELPER
+static const struct ctl_table uevent_helper_sysctl_table[] = {
+	{
+		.procname	= "hotplug",
+		.data		= &uevent_helper,
+		.maxlen		= UEVENT_HELPER_PATH_LEN,
+		.mode		= 0644,
+		.proc_handler	= proc_dostring,
+	},
+};
+
+static int __init init_uevent_helper_sysctl(void)
+{
+	register_sysctl_init("kernel", uevent_helper_sysctl_table);
+	return 0;
+}
+
+postcore_initcall(init_uevent_helper_sysctl);
+#endif

mm/memory.c

@@ -125,6 +125,24 @@ int randomize_va_space __read_mostly =
 					2;
 #endif
 
+static const struct ctl_table mmu_sysctl_table[] = {
+	{
+		.procname	= "randomize_va_space",
+		.data		= &randomize_va_space,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+};
+
+static int __init init_mm_sysctl(void)
+{
+	register_sysctl_init("kernel", mmu_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_mm_sysctl);
+
 #ifndef arch_wants_old_prefaulted_pte
 static inline bool arch_wants_old_prefaulted_pte(void)
 {

scripts/check-sysctl-docs

@@ -1,4 +1,4 @@
-#!/usr/bin/gawk -f
+#!/usr/bin/env -S gawk -f
 # SPDX-License-Identifier: GPL-2.0
 
 # Script to check sysctl documentation against source files
@@ -13,10 +13,22 @@
 # Specify -vdebug=1 to see debugging information
 
 BEGIN {
-    if (!table) {
+	if (!table) {
 	print "Please specify the table to look for using the table variable" > "/dev/stderr"
 	exit 1
-    }
+	}
+
+	# Documentation title skiplist
+	skiplist[0] = "^Documentation for"
+	skiplist[1] = "Network core options$"
+	skiplist[2] = "POSIX message queues filesystem$"
+	skiplist[3] = "Configuration options"
+	skiplist[4] = ". /proc/sys/fs"
+	skiplist[5] = "^Introduction$"
+	skiplist[6] = "^seccomp$"
+	skiplist[7] = "^pty$"
+	skiplist[8] = "^firmware_config$"
+	skiplist[9] = "^random$"
 }
 
 # The following globals are used:
@@ -31,124 +43,132 @@ BEGIN {
 
 # Remove punctuation from the given value
 function trimpunct(value) {
-    while (value ~ /^["&]/) {
+	while (value ~ /^["&]/) {
-	value = substr(value, 2)
+		value = substr(value, 2)
-    }
+	}
-    while (value ~ /[]["&,}]$/) {
+	while (value ~ /[]["&,}]$/) {
-	value = substr(value, 1, length(value) - 1)
+		value = substr(value, 1, length(value) - 1)
-    }
+	}
-    return value
+	return value
 }
 
 # Print the information for the given entry
 function printentry(entry) {
-    seen[entry]++
+	seen[entry]++
-    printf "* %s from %s", entry, file[entry]
+	printf "* %s from %s", entry, file[entry]
-    if (documented[entry]) {
+	if (documented[entry]) {
-	printf " (documented)"
+		printf " (documented)"
-    }
+	}
-    print ""
+	print ""
 }
 
 
 # Stage 1: build the list of documented entries
 FNR == NR && /^=+$/ {
-    if (prevline ~ /Documentation for/) {
+	for (i in skiplist) {
-	# This is the main title
+		if (prevline ~ skiplist[i]) {
-	next
+			next
-    }
+		}
+	}
 
-    # The previous line is a section title, parse it
+	# The previous line is a section title, parse it
-    $0 = prevline
+	$0 = prevline
-    if (debug) print "Parsing " $0
+	if (debug) print "Parsing " $0
-    inbrackets = 0
+	inbrackets = 0
-    for (i = 1; i <= NF; i++) {
+	for (i = 1; i <= NF; i++) {
-	if (length($i) == 0) {
+		if (length($i) == 0) {
-	    continue
+			continue
+		}
+		if (!inbrackets && substr($i, 1, 1) == "(") {
+			inbrackets = 1
+		}
+		if (!inbrackets) {
+			token = trimpunct($i)
+			if (length(token) > 0 && token != "and") {
+				if (debug) print trimpunct($i)
+					documented[trimpunct($i)]++
+			}
+		}
+		if (inbrackets && substr($i, length($i), 1) == ")") {
+			inbrackets = 0
+		}
 	}
-	if (!inbrackets && substr($i, 1, 1) == "(") {
-	    inbrackets = 1
-	}
-	if (!inbrackets) {
-	    token = trimpunct($i)
-	    if (length(token) > 0 && token != "and") {
-		if (debug) print trimpunct($i)
-		documented[trimpunct($i)]++
-	    }
-	}
-	if (inbrackets && substr($i, length($i), 1) == ")") {
-	    inbrackets = 0
-	}
-    }
 }
 
 FNR == NR {
-    prevline = $0
+	prevline = $0
-    next
+	next
 }
 
 
 # Stage 2: process each file and find all sysctl tables
 BEGINFILE {
-    delete entries
+	delete entries
-    curtable = ""
+	curtable = ""
-    curentry = ""
+	curentry = ""
-    delete vars
+	delete vars
-    if (debug) print "Processing file " FILENAME
+	if (debug) print "Processing file " FILENAME
 }
 
 /^static( const)? struct ctl_table/ {
-    match($0, /static( const)? struct ctl_table ([^][]+)/, tables)
+	match($0, /static( const)? struct ctl_table ([^][]+)/, tables)
-    curtable = tables[2]
+	curtable = tables[2]
-    if (debug) print "Processing table " curtable
+	if (debug) print "Processing table " curtable
 }
 
 /^};$/ {
-    curtable = ""
+	curtable = ""
-    curentry = ""
+	curentry = ""
-    delete vars
+	delete vars
 }
 
 curtable && /\.procname[\t ]*=[\t ]*".+"/ {
-    match($0, /.procname[\t ]*=[\t ]*"([^"]+)"/, names)
+	match($0, /.procname[\t ]*=[\t ]*"([^"]+)"/, names)
-    curentry = names[1]
+	curentry = names[1]
-    if (debug) print "Adding entry " curentry " to table " curtable
+	if (debug) print "Adding entry " curentry " to table " curtable
-    entries[curtable][curentry]++
+	entries[curtable][curentry]++
-    file[curentry] = FILENAME
+	file[curentry] = FILENAME
+}
+
+curtable && /UCOUNT_ENTRY.*/ {
+	match($0, /UCOUNT_ENTRY\("([^"]+)"\)/, names)
+	curentry = names[1]
+	if (debug) print "Adding entry " curentry " to table " curtable
+	entries[curtable][curentry]++
+	file[curentry] = FILENAME
 }
 
 /register_sysctl.*/ {
-    match($0, /register_sysctl(|_init|_sz)\("([^"]+)" *, *([^,)]+)/, tables)
+	match($0, /register_sysctl(|_init|_sz)\("([^"]+)" *, *([^,)]+)/, tables)
-    if (debug) print "Registering table " tables[3] " at " tables[2]
+	if (debug) print "Registering table " tables[3] " at " tables[2]
-    if (tables[2] == table) {
+	if (tables[2] == table) {
-        for (entry in entries[tables[3]]) {
+		for (entry in entries[tables[3]]) {
-            printentry(entry)
+			printentry(entry)
-        }
+		}
-    }
+	}
 }
 
 /kmemdup.*/ {
-    match($0, /([^ \t]+) *= *kmemdup\(([^,]+) *,/, names)
+	match($0, /([^ \t]+) *= *kmemdup\(([^,]+) *,/, names)
-    if (debug) print "Found variable " names[1] " for table " names[2]
+	if (debug) print "Found variable " names[1] " for table " names[2]
-    if (names[2] in entries) {
+	if (names[2] in entries) {
-        vars[names[1]] = names[2]
+		vars[names[1]] = names[2]
-    }
+	}
 }
 
 /__register_sysctl_table.*/ {
-    match($0, /__register_sysctl_table\([^,]+, *"([^"]+)" *, *([^,]+)/, tables)
+	match($0, /__register_sysctl_table\([^,]+, *"([^"]+)" *, *([^,]+)/, tables)
-    if (debug) print "Registering variable table " tables[2] " at " tables[1]
+	if (debug) print "Registering variable table " tables[2] " at " tables[1]
-    if (tables[1] == table && tables[2] in vars) {
+	if (tables[1] == table && tables[2] in vars) {
-        for (entry in entries[vars[tables[2]]]) {
+		for (entry in entries[vars[tables[2]]]) {
-            printentry(entry)
+			printentry(entry)
-        }
+		}
-    }
+	}
 }
 
 END {
-    for (entry in documented) {
+	for (entry in documented) {
-	if (!seen[entry]) {
+		if (!seen[entry])
-	    print "No implementation for " entry
+			print "No implementation for " entry
 	}
-    }
 }

tools/testing/selftests/sysctl/sysctl.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1
 # Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org>