Re: [PATCH v4 3/6] cxl/events: Update General Media Event Record to CXL spec rev 3.1

[Steven Rostedt]

On Wed, 27 Nov 2024 18:20:26 +0000
Shiju Jose <shiju.jose@xxxxxxxxxx> wrote:

> I tested removing hdr_uuid and region_uuid from the rasdaemon test setup
> as you suggested. As a result, libtraceevent parses correctly, as you mentioned.
> 
> However, I encounter  similar parsing error ("FAILED TO PARSE") when I add two additional
> decoded strings (%s) to the TP_printk, replacing (%u). Please see the attached format file,
> "format_cxl_general_media_v3.1_basic", for your reference.

Are you sure. I don't see anything wrong with that one. Which version of
libtraceevent do you have?

> 
> I've also attached another format file, "format_cxl_general_media_v3.1_full",
> which contains the complete TP_printk() intended.

This one has some complex arguments and also uses the '&' address of an
argument.

>  
> Can you please help or else can you share how to debug these errors in the
> libtraceevent setup?

Basically, I use the attached program (that just links to libtraceevent).

Note, I need to delete the first line of your files, which has the "cat"
command. But you can run this on the file itself:

  ./tep_load_event /sys/kernel/tracing/events/cxl/cxl_general_media/format

But you may need to be root to do that. If root just copies that file, you
can then run it as non-root.

 # cp /sys/kernel/tracing/events/cxl/cxl_general_media/format /tmp
 $ ./tep_load_event /tmp/format

I run it under gdb and see where it fails. But it should let you know if it
will pass or not. I put a breakpoint on tep_warning and when it gets hit, I
examine what it did up to that point.

-- Steve

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#include <event-parse.h>

static char *argv0;

static char *get_this_name(void)
{
	static char *this_name;
	char *arg;
	char *p;

	if (this_name)
		return this_name;

	arg = argv0;
	p = arg+strlen(arg);

	while (p >= arg && *p != '/')
		p--;
	p++;

	this_name = p;
	return p;
}

static void usage(void)
{
	char *p = get_this_name();

	printf("usage: %s exec\n"
	       "\n",p);
	exit(-1);
}

static void __vdie(const char *fmt, va_list ap, int err)
{
	int ret = errno;
	char *p = get_this_name();

	if (err && errno)
		perror(p);
	else
		ret = -1;

	fprintf(stderr, "  ");
	vfprintf(stderr, fmt, ap);

	fprintf(stderr, "\n");
	exit(ret);
}

void die(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__vdie(fmt, ap, 0);
	va_end(ap);
}

void pdie(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__vdie(fmt, ap, 1);
	va_end(ap);
}

int main (int argc, char **argv)
{
	struct tep_handle *tep;
	off_t size;
	char *buf;
	int ret;

	argv0 = argv[0];

	if (argc < 2)
		usage();

	tep = tep_alloc();
	if (!tep)
		pdie("tep_alloc");

	tep_set_loglevel(TEP_LOG_ALL);

	ret = open(argv[1], O_RDONLY);
	if (ret < 0)
		pdie(argv[1]);
	size = lseek(ret, 0, SEEK_END);
	if (size < 0)
		pdie("lseek");

	lseek(ret, 0, SEEK_SET);
	buf = malloc(size);
	if (!buf)
		pdie("malloc");

	size = read(ret, buf, size);
	if (size < 0)
		pdie("read");
	close(ret);

	ret = tep_parse_event(tep, buf, size, "sys");
	if (ret < 0)
		pdie("tep_parse_event");

	free(buf);
	tep_free(tep);
	return 0;
}