The permissions for the kernel.nmi_watchdog sysctl have always been
set at compile time despite the fact that a watchdog can fail to
probe. Let's fix this and set the permissions based on whether the
hardlockup detector actually probed.
Fixes: a994a3147e4c ("watchdog/hardlockup/perf: Implement init time detection of perf")
Reported-by: Petr Mladek <pmladek@xxxxxxxx>
Closes: https://lore.kernel.org/r/ZHCn4hNxFpY5-9Ki@alley
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
include/linux/nmi.h | 6 ------
kernel/watchdog.c | 30 ++++++++++++++++++++----------
2 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 333465e235e1..3a27169ec383 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -95,12 +95,6 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs);
static inline void arch_touch_nmi_watchdog(void) { }
#endif
-#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
-# define NMI_WATCHDOG_SYSCTL_PERM 0644
-#else
-# define NMI_WATCHDOG_SYSCTL_PERM 0444
-#endif
-
#if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
extern void hardlockup_detector_perf_stop(void);
extern void hardlockup_detector_perf_restart(void);
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 237990e8d345..4b9e31edb47f 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -880,15 +880,6 @@ static struct ctl_table watchdog_sysctls[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = (void *)&sixty,
},
- {
- .procname = "nmi_watchdog",
- .data = &watchdog_hardlockup_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,
@@ -952,10 +943,28 @@ static struct ctl_table watchdog_sysctls[] = {
{}
};
+static struct ctl_table watchdog_hardlockup_sysctl[] = {
+ {
+ .procname = "nmi_watchdog",
+ .data = &watchdog_hardlockup_user_enabled,
+ .maxlen = sizeof(int),
+ .mode = 0444,
+ .proc_handler = proc_nmi_watchdog,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
+ {}
+};
+
static void __init watchdog_sysctl_init(void)
{
register_sysctl_init("kernel", watchdog_sysctls);
+
+ if (watchdog_hardlockup_available)
+ watchdog_hardlockup_sysctl[0].mode = 0644;
+ register_sysctl_init("kernel", watchdog_hardlockup_sysctl);
}
+
#else
#define watchdog_sysctl_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
@@ -1011,6 +1020,8 @@ static int __init lockup_detector_check(void)
/* Make sure no work is pending. */
flush_work(&detector_work);
+ watchdog_sysctl_init();
+
return 0;
}
@@ -1030,5 +1041,4 @@ void __init lockup_detector_init(void)
allow_lockup_detector_init_retry = true;
lockup_detector_setup();
- watchdog_sysctl_init();
}
--
2.41.0.rc0.172.g3f132b7071-goog
