[3/4] watchdog: move watchdog sysctl to watchdog.c

Commit Message

Xiaoming Ni May 15, 2020, 4:33 a.m. UTC

Move watchdog sysctl interface to watchdog.c.
Use register_sysctl() to register the sysctl interface to avoid
merge conflicts when different features modify sysctl.c at the same time.

Signed-off-by: Xiaoming Ni <[e-mail]>
---
 kernel/sysctl.c   |  96 --------------------------------------------
 kernel/watchdog.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+), 96 deletions(-)

Comments

Kees Cook May 15, 2020, 8:09 a.m. UTC | #1

On Fri, May 15, 2020 at 12:33:43PM +0800, Xiaoming Ni wrote:
> +static int sixty = 60;

This should be const. (Which will require a cast during extra2
assignment.)

Xiaoming Ni May 15, 2020, 9:17 a.m. UTC | #2

On 2020/5/15 16:09, Kees Cook wrote:
> On Fri, May 15, 2020 at 12:33:43PM +0800, Xiaoming Ni wrote:
>> +static int sixty = 60;
> 
> This should be const. (Which will require a cast during extra2
> assignment.)
> 
Sorry, I forgot to append const.
Thanks for your guidance.

Thanks
Xiaoming Ni

Patch

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 01fc559..e394990 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -97,9 +97,6 @@ 
 #ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
 #include <linux/stackleak.h>
 #endif
-#ifdef CONFIG_LOCKUP_DETECTOR
-#include <linux/nmi.h>
-#endif
 
 #if defined(CONFIG_SYSCTL)
 
@@ -120,9 +117,6 @@ 
 #endif
 
 /* Constants used for minimum and  maximum */
-#ifdef CONFIG_LOCKUP_DETECTOR
-static int sixty = 60;
-#endif
 
 static int __maybe_unused two = 2;
 static int __maybe_unused four = 4;
@@ -887,96 +881,6 @@  static int sysrq_sysctl_handler(struct ctl_table *table, int write,
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec,
 	},
-#if defined(CONFIG_LOCKUP_DETECTOR)
-	{
-		.procname       = "watchdog",
-		.data		= &watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler   = proc_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "watchdog_thresh",
-		.data		= &watchdog_thresh,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_watchdog_thresh,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &sixty,
-	},
-	{
-		.procname       = "nmi_watchdog",
-		.data		= &nmi_watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
-		.proc_handler   = proc_nmi_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "watchdog_cpumask",
-		.data		= &watchdog_cpumask_bits,
-		.maxlen		= NR_CPUS,
-		.mode		= 0644,
-		.proc_handler	= proc_watchdog_cpumask,
-	},
-#ifdef CONFIG_SOFTLOCKUP_DETECTOR
-	{
-		.procname       = "soft_watchdog",
-		.data		= &soft_watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler   = proc_soft_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "softlockup_panic",
-		.data		= &softlockup_panic,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#ifdef CONFIG_SMP
-	{
-		.procname	= "softlockup_all_cpu_backtrace",
-		.data		= &sysctl_softlockup_all_cpu_backtrace,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#endif /* CONFIG_SMP */
-#endif
-#ifdef CONFIG_HARDLOCKUP_DETECTOR
-	{
-		.procname	= "hardlockup_panic",
-		.data		= &hardlockup_panic,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#ifdef CONFIG_SMP
-	{
-		.procname	= "hardlockup_all_cpu_backtrace",
-		.data		= &sysctl_hardlockup_all_cpu_backtrace,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#endif /* CONFIG_SMP */
-#endif
-#endif
-
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 	{
 		.procname       = "unknown_nmi_panic",
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index b6b1f54..05e1d58 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -23,6 +23,9 @@ 
 #include <linux/sched/debug.h>
 #include <linux/sched/isolation.h>
 #include <linux/stop_machine.h>
+#ifdef CONFIG_SYSCTL
+#include <linux/kmemleak.h>
+#endif
 
 #include <asm/irq_regs.h>
 #include <linux/kvm_para.h>
@@ -756,10 +759,124 @@  int proc_watchdog_cpumask(struct ctl_table *table, int write,
 	mutex_unlock(&watchdog_mutex);
 	return err;
 }
+
+static int sixty = 60;
+
+static struct ctl_table watchdog_sysctls[] = {
+	{
+		.procname       = "watchdog",
+		.data		= &watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler   = proc_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "watchdog_thresh",
+		.data		= &watchdog_thresh,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_watchdog_thresh,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= &sixty,
+	},
+	{
+		.procname       = "nmi_watchdog",
+		.data		= &nmi_watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
+		.proc_handler   = proc_nmi_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "watchdog_cpumask",
+		.data		= &watchdog_cpumask_bits,
+		.maxlen		= NR_CPUS,
+		.mode		= 0644,
+		.proc_handler	= proc_watchdog_cpumask,
+	},
+#ifdef CONFIG_SOFTLOCKUP_DETECTOR
+	{
+		.procname       = "soft_watchdog",
+		.data		= &soft_watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler   = proc_soft_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "softlockup_panic",
+		.data		= &softlockup_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_SMP
+	{
+		.procname	= "softlockup_all_cpu_backtrace",
+		.data		= &sysctl_softlockup_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+#endif
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+	{
+		.procname	= "hardlockup_panic",
+		.data		= &hardlockup_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_SMP
+	{
+		.procname	= "hardlockup_all_cpu_backtrace",
+		.data		= &sysctl_hardlockup_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+#endif
+	{}
+};
+
+/*
+ * The watchdog sysctl has a default value.
+ * Even if register_sysctl() fails, it does not affect the main function of
+ * the watchdog. At the same time, during the system initialization phase,
+ * malloc small memory will almost never fail.
+ * So the return value is ignored here
+ */
+static void __init watchdog_sysctl_init(void)
+{
+	struct ctl_table_header *p = register_sysctl("kernel", watchdog_sysctls);
+
+	if (unlikely(!p)) {
+		pr_err("%s fail\n", __func__);
+		return;
+	}
+	kmemleak_not_leak(p);
+}
+#else
+#define watchdog_sysctl_init() do { } while (0)
 #endif /* CONFIG_SYSCTL */
 
 void __init lockup_detector_init(void)
 {
+	watchdog_sysctl_init();
 	if (tick_nohz_full_enabled())
 		pr_info("Disabling watchdog on nohz_full cores by default\n");