[ltt-dev] [PATCH v3 1/1] add tracepoints of panic and kexec

[compudj@krystal.dyndns.org (Mathieu Desnoyers)]

* Zhaolei (zhaolei at cn.fujitsu.com) wrote:
> Instrumentation of following panic and kexec related events are added:
> 	panic
> 	kernel_kexec
> 	crash_kexec
> 
> It is useful for build flight-recorder program based on lttng infrastructure.
> 
> Signed-off-by: Zhao Lei <zhaolei at cn.fujitsu.com>
> ---
>  include/trace/notifier.h |   17 +++++++++++++++++
>  kernel/kexec.c           |    8 ++++++++
>  kernel/panic.c           |    7 +++++++
>  3 files changed, 32 insertions(+), 0 deletions(-)
>  create mode 100644 include/trace/notifier.h
> 
> diff --git a/include/trace/notifier.h b/include/trace/notifier.h

Hi Zhaolei,

By saying "using notifier.h", I meant "using include/linux/notifier.h",
the standard kernel header, with a standard notifier call chain. Sorry
for the misunderstanding.

Mathieu


> new file mode 100644
> index 0000000..0eb721b
> --- /dev/null
> +++ b/include/trace/notifier.h
> @@ -0,0 +1,17 @@
> +#ifndef _TRACE_NOTIFIER_H
> +#define _TRACE_NOTIFIER_H
> +
> +#include <linux/tracepoint.h>
> +#include <linux/kexec.h>
> +
> +DECLARE_TRACE(notifier_panic,
> +	TPPROTO(const char *fmt, va_list args),
> +	TPARGS(fmt, args));
> +DECLARE_TRACE(notifier_kernel_kexec,
> +	TPPROTO(struct kimage *image),
> +	TPARGS(image));
> +DECLARE_TRACE(notifier_crash_kexec,
> +	TPPROTO(struct kimage *image, struct pt_regs *regs),
> +	TPARGS(image, regs));
> +
> +#endif
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index aef2653..4de87cc 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -30,6 +30,7 @@
>  #include <linux/pm.h>
>  #include <linux/cpu.h>
>  #include <linux/console.h>
> +#include <trace/notifier.h>
>  
>  #include <asm/page.h>
>  #include <asm/uaccess.h>
> @@ -37,6 +38,9 @@
>  #include <asm/system.h>
>  #include <asm/sections.h>
>  
> +DEFINE_TRACE(notifier_kernel_kexec);
> +DEFINE_TRACE(notifier_crash_kexec);
> +
>  /* Per cpu memory for storing cpu states in case of system crash. */
>  note_buf_t* crash_notes;
>  
> @@ -1062,6 +1066,8 @@ asmlinkage long compat_sys_kexec_load(unsigned long entry,
>  
>  void crash_kexec(struct pt_regs *regs)
>  {
> +	trace_notifier_crash_kexec(kexec_crash_image, regs);
> +
>  	/* Take the kexec_mutex here to prevent sys_kexec_load
>  	 * running on one cpu from replacing the crash kernel
>  	 * we are using after a panic on a different cpu.
> @@ -1428,6 +1434,8 @@ int kernel_kexec(void)
>  {
>  	int error = 0;
>  
> +	trace_notifier_kernel_kexec(kexec_image);
> +
>  	if (!mutex_trylock(&kexec_mutex))
>  		return -EBUSY;
>  	if (!kexec_image) {
> diff --git a/kernel/panic.c b/kernel/panic.c
> index 12c5a0a..d1be86c 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -21,6 +21,9 @@
>  #include <linux/debug_locks.h>
>  #include <linux/random.h>
>  #include <linux/kallsyms.h>
> +#include <trace/notifier.h>
> +
> +DEFINE_TRACE(notifier_panic);
>  
>  int panic_on_oops;
>  int tainted;
> @@ -68,6 +71,10 @@ NORET_TYPE void panic(const char * fmt, ...)
>  	unsigned long caller = (unsigned long) __builtin_return_address(0);
>  #endif
>  
> +	va_start(args, fmt);
> +	trace_notifier_panic(fmt, args);
> +	va_end(args);
> +
>  	/*
>  	 * It's possible to come here directly from a panic-assertion and not
>  	 * have preempt disabled. Some functions called from here want
> -- 
> 1.5.5.3
> 
> 
> 
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-- 
Mathieu Desnoyers
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