55537871ef
In many cases of hardlockup reports, it's actually not possible to know why it triggered, because the CPU that got stuck is usually waiting on a resource (with IRQs disabled) in posession of some other CPU is holding. IOW, we are often looking at the stacktrace of the victim and not the actual offender. Introduce sysctl / cmdline parameter that makes it possible to have hardlockup detector perform all-CPU backtrace. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Acked-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
106 lines
2.7 KiB
C
106 lines
2.7 KiB
C
/*
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* linux/include/linux/nmi.h
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*/
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#ifndef LINUX_NMI_H
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#define LINUX_NMI_H
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#include <linux/sched.h>
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#include <asm/irq.h>
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/**
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* touch_nmi_watchdog - restart NMI watchdog timeout.
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*
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* If the architecture supports the NMI watchdog, touch_nmi_watchdog()
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* may be used to reset the timeout - for code which intentionally
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* disables interrupts for a long time. This call is stateless.
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*/
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#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
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#include <asm/nmi.h>
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extern void touch_nmi_watchdog(void);
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#else
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static inline void touch_nmi_watchdog(void)
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{
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touch_softlockup_watchdog();
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}
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#endif
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#if defined(CONFIG_HARDLOCKUP_DETECTOR)
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extern void hardlockup_detector_disable(void);
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#else
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static inline void hardlockup_detector_disable(void) {}
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#endif
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/*
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* Create trigger_all_cpu_backtrace() out of the arch-provided
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* base function. Return whether such support was available,
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* to allow calling code to fall back to some other mechanism:
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*/
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#ifdef arch_trigger_all_cpu_backtrace
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static inline bool trigger_all_cpu_backtrace(void)
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{
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arch_trigger_all_cpu_backtrace(true);
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return true;
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}
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static inline bool trigger_allbutself_cpu_backtrace(void)
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{
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arch_trigger_all_cpu_backtrace(false);
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return true;
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}
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/* generic implementation */
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void nmi_trigger_all_cpu_backtrace(bool include_self,
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void (*raise)(cpumask_t *mask));
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bool nmi_cpu_backtrace(struct pt_regs *regs);
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#else
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static inline bool trigger_all_cpu_backtrace(void)
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{
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return false;
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}
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static inline bool trigger_allbutself_cpu_backtrace(void)
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{
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return false;
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}
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#endif
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#ifdef CONFIG_LOCKUP_DETECTOR
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int hw_nmi_is_cpu_stuck(struct pt_regs *);
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u64 hw_nmi_get_sample_period(int watchdog_thresh);
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extern int nmi_watchdog_enabled;
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extern int soft_watchdog_enabled;
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extern int watchdog_user_enabled;
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extern int watchdog_thresh;
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extern unsigned long *watchdog_cpumask_bits;
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extern int sysctl_softlockup_all_cpu_backtrace;
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extern int sysctl_hardlockup_all_cpu_backtrace;
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struct ctl_table;
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extern int proc_watchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_nmi_watchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_soft_watchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_watchdog_thresh(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_watchdog_cpumask(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int lockup_detector_suspend(void);
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extern void lockup_detector_resume(void);
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#else
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static inline int lockup_detector_suspend(void)
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{
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return 0;
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}
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static inline void lockup_detector_resume(void)
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{
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}
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#endif
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#ifdef CONFIG_HAVE_ACPI_APEI_NMI
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#include <asm/nmi.h>
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#endif
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#endif
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