sysctl-6.7-rc1

To help make the move of sysctls out of kernel/sysctl.c not incur a size
 penalty sysctl has been changed to allow us to not require the sentinel, the
 final empty element on the sysctl array. Joel Granados has been doing all this
 work. On the v6.6 kernel we got the major infrastructure changes required to
 support this. For v6.7-rc1 we have all arch/ and drivers/ modified to remove
 the sentinel. Both arch and driver changes have been on linux-next for a bit
 less than a month. It is worth re-iterating the value:
 
   - this helps reduce the overall build time size of the kernel and run time
      memory consumed by the kernel by about ~64 bytes per array
   - the extra 64-byte penalty is no longer inncurred now when we move sysctls
     out from kernel/sysctl.c to their own files
 
 For v6.8-rc1 expect removal of all the sentinels and also then the unneeded
 check for procname == NULL.
 
 The last 2 patches are fixes recently merged by Krister Johansen which allow
 us again to use softlockup_panic early on boot. This used to work but the
 alias work broke it. This is useful for folks who want to detect softlockups
 super early rather than wait and spend money on cloud solutions with nothing
 but an eventual hung kernel. Although this hadn't gone through linux-next it's
 also a stable fix, so we might as well roll through the fixes now.
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Merge tag 'sysctl-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull sysctl updates from Luis Chamberlain:
 "To help make the move of sysctls out of kernel/sysctl.c not incur a
  size penalty sysctl has been changed to allow us to not require the
  sentinel, the final empty element on the sysctl array. Joel Granados
  has been doing all this work. On the v6.6 kernel we got the major
  infrastructure changes required to support this. For v6.7-rc1 we have
  all arch/ and drivers/ modified to remove the sentinel. Both arch and
  driver changes have been on linux-next for a bit less than a month. It
  is worth re-iterating the value:

   - this helps reduce the overall build time size of the kernel and run
     time memory consumed by the kernel by about ~64 bytes per array

   - the extra 64-byte penalty is no longer inncurred now when we move
     sysctls out from kernel/sysctl.c to their own files

  For v6.8-rc1 expect removal of all the sentinels and also then the
  unneeded check for procname == NULL.

  The last two patches are fixes recently merged by Krister Johansen
  which allow us again to use softlockup_panic early on boot. This used
  to work but the alias work broke it. This is useful for folks who want
  to detect softlockups super early rather than wait and spend money on
  cloud solutions with nothing but an eventual hung kernel. Although
  this hadn't gone through linux-next it's also a stable fix, so we
  might as well roll through the fixes now"

* tag 'sysctl-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (23 commits)
  watchdog: move softlockup_panic back to early_param
  proc: sysctl: prevent aliased sysctls from getting passed to init
  intel drm: Remove now superfluous sentinel element from ctl_table array
  Drivers: hv: Remove now superfluous sentinel element from ctl_table array
  raid: Remove now superfluous sentinel element from ctl_table array
  fw loader: Remove the now superfluous sentinel element from ctl_table array
  sgi-xp: Remove the now superfluous sentinel element from ctl_table array
  vrf: Remove the now superfluous sentinel element from ctl_table array
  char-misc: Remove the now superfluous sentinel element from ctl_table array
  infiniband: Remove the now superfluous sentinel element from ctl_table array
  macintosh: Remove the now superfluous sentinel element from ctl_table array
  parport: Remove the now superfluous sentinel element from ctl_table array
  scsi: Remove now superfluous sentinel element from ctl_table array
  tty: Remove now superfluous sentinel element from ctl_table array
  xen: Remove now superfluous sentinel element from ctl_table array
  hpet: Remove now superfluous sentinel element from ctl_table array
  c-sky: Remove now superfluous sentinel element from ctl_talbe array
  powerpc: Remove now superfluous sentinel element from ctl_table arrays
  riscv: Remove now superfluous sentinel element from ctl_table array
  x86/vdso: Remove now superfluous sentinel element from ctl_table array
  ...

arch/arm/kernel/isa.c

@@ -16,7 +16,7 @@
 
 static unsigned int isa_membase, isa_portbase, isa_portshift;
 
-static struct ctl_table ctl_isa_vars[4] = {
+static struct ctl_table ctl_isa_vars[] = {
 	{
 		.procname	= "membase",
 		.data		= &isa_membase, 
@@ -35,7 +35,7 @@ static struct ctl_table ctl_isa_vars[4] = {
 		.maxlen		= sizeof(isa_portshift),
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec,
-	}, {}
+	},
 };
 
 static struct ctl_table_header *isa_sysctl_header;

arch/arm64/kernel/armv8_deprecated.c

@@ -52,10 +52,8 @@ struct insn_emulation {
 	int min;
 	int max;
 
-	/*
-	 * sysctl for this emulation + a sentinal entry.
-	 */
-	struct ctl_table sysctl[2];
+	/* sysctl for this emulation */
+	struct ctl_table sysctl;
 };
 
 #define ARM_OPCODE_CONDTEST_FAIL   0
@@ -558,7 +556,7 @@ static void __init register_insn_emulation(struct insn_emulation *insn)
 	update_insn_emulation_mode(insn, INSN_UNDEF);
 
 	if (insn->status != INSN_UNAVAILABLE) {
-		sysctl = &insn->sysctl[0];
+		sysctl = &insn->sysctl;
 
 		sysctl->mode = 0644;
 		sysctl->maxlen = sizeof(int);

arch/arm64/kernel/fpsimd.c

@@ -589,7 +589,6 @@ static struct ctl_table sve_default_vl_table[] = {
 		.proc_handler	= vec_proc_do_default_vl,
 		.extra1		= &vl_info[ARM64_VEC_SVE],
 	},
-	{ }
 };
 
 static int __init sve_sysctl_init(void)
@@ -613,7 +612,6 @@ static struct ctl_table sme_default_vl_table[] = {
 		.proc_handler	= vec_proc_do_default_vl,
 		.extra1		= &vl_info[ARM64_VEC_SME],
 	},
-	{ }
 };
 
 static int __init sme_sysctl_init(void)

arch/arm64/kernel/process.c

@@ -724,7 +724,6 @@ static struct ctl_table tagged_addr_sysctl_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 static int __init tagged_addr_init(void)

arch/csky/abiv1/alignment.c

@@ -329,7 +329,6 @@ static struct ctl_table alignment_tbl[5] = {
 		.mode = 0666,
 		.proc_handler = &proc_dointvec
 	},
-	{}
 };
 
 static int __init csky_alignment_init(void)

arch/powerpc/kernel/idle.c

@@ -105,7 +105,6 @@ static struct ctl_table powersave_nap_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{}
 };
 
 static int __init

arch/powerpc/platforms/pseries/mobility.c

@@ -61,7 +61,6 @@ static struct ctl_table nmi_wd_lpm_factor_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_douintvec_minmax,
 	},
-	{}
 };
 
 static int __init register_nmi_wd_lpm_factor_sysctl(void)

arch/riscv/kernel/vector.c

@@ -255,7 +255,6 @@ static struct ctl_table riscv_v_default_vstate_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dobool,
 	},
-	{ }
 };
 
 static int __init riscv_v_sysctl_init(void)

arch/s390/appldata/appldata_base.c

@@ -63,7 +63,6 @@ static struct ctl_table appldata_table[] = {
 		.mode		= S_IRUGO | S_IWUSR,
 		.proc_handler	= appldata_interval_handler,
 	},
-	{ },
 };
 
 /*
@@ -351,8 +350,7 @@ int appldata_register_ops(struct appldata_ops *ops)
 	if (ops->size > APPLDATA_MAX_REC_SIZE)
 		return -EINVAL;
 
-	/* The last entry must be an empty one */
-	ops->ctl_table = kcalloc(2, sizeof(struct ctl_table), GFP_KERNEL);
+	ops->ctl_table = kcalloc(1, sizeof(struct ctl_table), GFP_KERNEL);
 	if (!ops->ctl_table)
 		return -ENOMEM;
 

arch/s390/kernel/debug.c

@@ -978,7 +978,6 @@ static struct ctl_table s390dbf_table[] = {
 		.mode		= S_IRUGO | S_IWUSR,
 		.proc_handler	= s390dbf_procactive,
 	},
-	{ }
 };
 
 static struct ctl_table_header *s390dbf_sysctl_header;

arch/s390/kernel/topology.c

@@ -636,7 +636,6 @@ static struct ctl_table topology_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= topology_ctl_handler,
 	},
-	{ },
 };
 
 static int __init topology_init(void)

arch/s390/mm/cmm.c

@@ -332,7 +332,6 @@ static struct ctl_table cmm_table[] = {
 		.mode		= 0644,
 		.proc_handler	= cmm_timeout_handler,
 	},
-	{ }
 };
 
 #ifdef CONFIG_CMM_IUCV

arch/s390/mm/pgalloc.c

@@ -30,7 +30,6 @@ static struct ctl_table page_table_sysctl[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 static int __init page_table_register_sysctl(void)

arch/x86/entry/vdso/vdso32-setup.c

@@ -67,7 +67,6 @@ static struct ctl_table abi_table2[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{}
 };
 
 static __init int ia32_binfmt_init(void)

arch/x86/kernel/cpu/intel.c

@@ -1003,7 +1003,6 @@ static struct ctl_table sld_sysctls[] = {
 		.extra1         = SYSCTL_ZERO,
 		.extra2         = SYSCTL_ONE,
 	},
-	{}
 };
 
 static int __init sld_mitigate_sysctl_init(void)

arch/x86/kernel/itmt.c

@@ -74,7 +74,6 @@ static struct ctl_table itmt_kern_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{}
 };
 
 static struct ctl_table_header *itmt_sysctl_header;

drivers/base/firmware_loader/fallback_table.c

@@ -44,7 +44,6 @@ static struct ctl_table firmware_config_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 static struct ctl_table_header *firmware_config_sysct_table_header;

drivers/char/hpet.c

@@ -709,7 +709,6 @@ static struct ctl_table hpet_table[] = {
 	 .mode = 0644,
 	 .proc_handler = proc_dointvec,
 	 },
-	{}
 };
 
 static struct ctl_table_header *sysctl_header;

drivers/char/ipmi/ipmi_poweroff.c

@@ -656,7 +656,6 @@ static struct ctl_table ipmi_table[] = {
 	  .maxlen	= sizeof(poweroff_powercycle),
 	  .mode		= 0644,
 	  .proc_handler	= proc_dointvec },
-	{ }
 };
 
 static struct ctl_table_header *ipmi_table_header;

drivers/char/random.c

@@ -1683,7 +1683,6 @@ static struct ctl_table random_table[] = {
 		.mode		= 0444,
 		.proc_handler	= proc_do_uuid,
 	},
-	{ }
 };
 
 /*

drivers/gpu/drm/i915/i915_perf.c

@@ -4836,7 +4836,6 @@ static struct ctl_table oa_table[] = {
 	 .extra1 = SYSCTL_ZERO,
 	 .extra2 = &oa_sample_rate_hard_limit,
 	 },
-	{}
 };
 
 static u32 num_perf_groups_per_gt(struct intel_gt *gt)

drivers/hv/hv_common.c

@@ -148,7 +148,6 @@ static struct ctl_table hv_ctl_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE
 	},
-	{}
 };
 
 static int hv_die_panic_notify_crash(struct notifier_block *self,

drivers/infiniband/core/iwcm.c

@@ -111,7 +111,6 @@ static struct ctl_table iwcm_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{ }
 };
 
 /*

drivers/infiniband/core/ucma.c

@@ -71,7 +71,6 @@ static struct ctl_table ucma_ctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{ }
 };
 
 struct ucma_file {

drivers/macintosh/mac_hid.c

@@ -236,7 +236,6 @@ static struct ctl_table mac_hid_files[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{ }
 };
 
 static struct ctl_table_header *mac_hid_sysctl_header;

drivers/md/md.c

@@ -304,7 +304,6 @@ static struct ctl_table raid_table[] = {
 		.mode		= S_IRUGO|S_IWUSR,
 		.proc_handler	= proc_dointvec,
 	},
-	{ }
 };
 
 static int start_readonly;

drivers/misc/sgi-xp/xpc_main.c

@@ -110,7 +110,6 @@ static struct ctl_table xpc_sys_xpc_hb[] = {
 	 .proc_handler = proc_dointvec_minmax,
 	 .extra1 = &xpc_hb_check_min_interval,
 	 .extra2 = &xpc_hb_check_max_interval},
-	{}
 };
 static struct ctl_table xpc_sys_xpc[] = {
 	{
@@ -121,7 +120,6 @@ static struct ctl_table xpc_sys_xpc[] = {
 	 .proc_handler = proc_dointvec_minmax,
 	 .extra1 = &xpc_disengage_min_timelimit,
 	 .extra2 = &xpc_disengage_max_timelimit},
-	{}
 };
 
 static struct ctl_table_header *xpc_sysctl;

drivers/net/vrf.c

@@ -1963,7 +1963,6 @@ static const struct ctl_table vrf_table[] = {
 		/* set by the vrf_netns_init */
 		.extra1		= NULL,
 	},
-	{ },
 };
 
 static int vrf_netns_init_sysctl(struct net *net, struct netns_vrf *nn_vrf)

drivers/parport/procfs.c

@@ -259,8 +259,12 @@ PARPORT_MAX_SPINTIME_VALUE;
 struct parport_sysctl_table {
 	struct ctl_table_header *port_header;
 	struct ctl_table_header *devices_header;
-	struct ctl_table vars[12];
-	struct ctl_table device_dir[2];
+#ifdef CONFIG_PARPORT_1284
+	struct ctl_table vars[10];
+#else
+	struct ctl_table vars[5];
+#endif /* IEEE 1284 support */
+	struct ctl_table device_dir[1];
 };
 
 static const struct parport_sysctl_table parport_sysctl_template = {
@@ -341,7 +345,6 @@ static const struct parport_sysctl_table parport_sysctl_template = {
 			.proc_handler	= do_autoprobe
 		},
 #endif /* IEEE 1284 support */
-		{}
 	},
 	{
 		{
@@ -351,19 +354,14 @@ static const struct parport_sysctl_table parport_sysctl_template = {
 			.mode		= 0444,
 			.proc_handler	= do_active_device
 		},
-		{}
 	},
 };
 
 struct parport_device_sysctl_table
 {
 	struct ctl_table_header *sysctl_header;
-	struct ctl_table vars[2];
-	struct ctl_table device_dir[2];
-	struct ctl_table devices_root_dir[2];
-	struct ctl_table port_dir[2];
-	struct ctl_table parport_dir[2];
-	struct ctl_table dev_dir[2];
+	struct ctl_table vars[1];
+	struct ctl_table device_dir[1];
 };
 
 static const struct parport_device_sysctl_table
@@ -379,7 +377,6 @@ parport_device_sysctl_template = {
 			.extra1		= (void*) &parport_min_timeslice_value,
 			.extra2		= (void*) &parport_max_timeslice_value
 		},
-		{}
 	},
 	{
 		{
@@ -388,17 +385,13 @@ parport_device_sysctl_template = {
 			.maxlen		= 0,
 			.mode		= 0555,
 		},
-		{}
 	}
 };
 
 struct parport_default_sysctl_table
 {
 	struct ctl_table_header *sysctl_header;
-	struct ctl_table vars[3];
-	struct ctl_table default_dir[2];
-	struct ctl_table parport_dir[2];
-	struct ctl_table dev_dir[2];
+	struct ctl_table vars[2];
 };
 
 static struct parport_default_sysctl_table
@@ -423,7 +416,6 @@ parport_default_sysctl_table = {
 			.extra1		= (void*) &parport_min_spintime_value,
 			.extra2		= (void*) &parport_max_spintime_value
 		},
-		{}
 	}
 };
 
@@ -443,7 +435,9 @@ int parport_proc_register(struct parport *port)
 	t->vars[0].data = &port->spintime;
 	for (i = 0; i < 5; i++) {
 		t->vars[i].extra1 = port;
+#ifdef CONFIG_PARPORT_1284
 		t->vars[5 + i].extra2 = &port->probe_info[i];
+#endif /* IEEE 1284 support */
 	}
 
 	port_name_len = strnlen(port->name, PARPORT_NAME_MAX_LEN);

drivers/perf/arm_pmuv3.c

@@ -1175,7 +1175,6 @@ static struct ctl_table armv8_pmu_sysctl_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 static void armv8_pmu_register_sysctl_table(void)

drivers/scsi/scsi_sysctl.c

@@ -18,7 +18,6 @@ static struct ctl_table scsi_table[] = {
 	  .maxlen	= sizeof(scsi_logging_level),
 	  .mode		= 0644,
 	  .proc_handler	= proc_dointvec },
-	{ }
 };
 
 static struct ctl_table_header *scsi_table_header;

drivers/scsi/sg.c

@@ -1650,7 +1650,6 @@ static struct ctl_table sg_sysctls[] = {
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec,
 	},
-	{}
 };
 
 static struct ctl_table_header *hdr;

drivers/tty/tty_io.c

@@ -3612,7 +3612,6 @@ static struct ctl_table tty_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 /*

drivers/xen/balloon.c

@@ -94,7 +94,6 @@ static struct ctl_table balloon_table[] = {
 		.extra1         = SYSCTL_ZERO,
 		.extra2         = SYSCTL_ONE,
 	},
-	{ }
 };
 
 #else

fs/proc/proc_sysctl.c

@@ -1576,7 +1576,6 @@ static const struct sysctl_alias sysctl_aliases[] = {
 	{"hung_task_panic",			"kernel.hung_task_panic" },
 	{"numa_zonelist_order",			"vm.numa_zonelist_order" },
 	{"softlockup_all_cpu_backtrace",	"kernel.softlockup_all_cpu_backtrace" },
-	{"softlockup_panic",			"kernel.softlockup_panic" },
 	{ }
 };
 
@@ -1592,6 +1591,13 @@ static const char *sysctl_find_alias(char *param)
 	return NULL;
 }
 
+bool sysctl_is_alias(char *param)
+{
+	const char *alias = sysctl_find_alias(param);
+
+	return alias != NULL;
+}
+
 /* Set sysctl value passed on kernel command line. */
 static int process_sysctl_arg(char *param, char *val,
 			       const char *unused, void *arg)

include/linux/sysctl.h

@@ -242,6 +242,7 @@ extern void __register_sysctl_init(const char *path, struct ctl_table *table,
 extern struct ctl_table_header *register_sysctl_mount_point(const char *path);
 
 void do_sysctl_args(void);
+bool sysctl_is_alias(char *param);
 int do_proc_douintvec(struct ctl_table *table, int write,
 		      void *buffer, size_t *lenp, loff_t *ppos,
 		      int (*conv)(unsigned long *lvalp,
@@ -287,6 +288,11 @@ static inline void setup_sysctl_set(struct ctl_table_set *p,
 static inline void do_sysctl_args(void)
 {
 }
+
+static inline bool sysctl_is_alias(char *param)
+{
+	return false;
+}
 #endif /* CONFIG_SYSCTL */
 
 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,

init/main.c

@@ -530,6 +530,10 @@ static int __init unknown_bootoption(char *param, char *val,
 {
 	size_t len = strlen(param);
 
+	/* Handle params aliased to sysctls */
+	if (sysctl_is_alias(param))
+		return 0;
+
 	repair_env_string(param, val);
 
 	/* Handle obsolete-style parameters */

kernel/watchdog.c

@@ -283,6 +283,13 @@ static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
 static DEFINE_PER_CPU(bool, softlockup_touch_sync);
 static unsigned long soft_lockup_nmi_warn;
 
+static int __init softlockup_panic_setup(char *str)
+{
+	softlockup_panic = simple_strtoul(str, NULL, 0);
+	return 1;
+}
+__setup("softlockup_panic=", softlockup_panic_setup);
+
 static int __init nowatchdog_setup(char *str)
 {
 	watchdog_user_enabled = 0;