Re: [PATCH -tip v2 7/8] perf probe: Remove die() from probe-finder code

[Masami Hiramatsu <mhiramat at redhat dot com>]

Hi Arnaldo,

Has this code done what you suggested? :)
I'd like to have your comment.

Thank you,

Masami Hiramatsu wrote:
> Remove die() and DIE_IF() code from util/probe-finder.c since
> these 'sudden death' in utility functions make reusing it from
> other code (especially tui/gui) difficult.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> ---
> 
>  tools/perf/util/probe-event.c  |    4 
>  tools/perf/util/probe-finder.c |  517 +++++++++++++++++++++++++---------------
>  2 files changed, 322 insertions(+), 199 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index bef2805..7893b32 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -151,10 +151,10 @@ static int try_to_find_kprobe_trace_events(struct perf_probe_event *pev,
>  
>  	/* Error path */
>  	if (need_dwarf) {
> -		if (ntevs == -ENOENT)
> +		if (ntevs == -EBADF)
>  			pr_warning("No dwarf info found in the vmlinux - "
>  				"please rebuild with CONFIG_DEBUG_INFO=y.\n");
> -		die("Could not analyze debuginfo.");
> +		die("Failed to analyze debuginfo.");
>  	}
>  	pr_debug("An error occurred in debuginfo analysis."
>  		 " Try to use symbols.\n");
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 1f45285..4a57504 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -196,19 +196,7 @@ static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
>  {
>  	const char *name;
>  	name = dwarf_diename(dw_die);
> -	DIE_IF(name == NULL);
> -	return strcmp(tname, name);
> -}
> -
> -/* Get entry pc(or low pc, 1st entry of ranges)  of the die */
> -static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
> -{
> -	Dwarf_Addr epc;
> -	int ret;
> -
> -	ret = dwarf_entrypc(dw_die, &epc);
> -	DIE_IF(ret == -1);
> -	return epc;
> +	return name ? strcmp(tname, name) : -1;
>  }
>  
>  /* Get type die, but skip qualifiers and typedef */
> @@ -390,7 +378,7 @@ static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
>   */
>  
>  /* Show a location */
> -static void convert_location(Dwarf_Op *op, struct probe_finder *pf)
> +static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
>  {
>  	unsigned int regn;
>  	Dwarf_Word offs = 0;
> @@ -400,8 +388,11 @@ static void convert_location(Dwarf_Op *op, struct probe_finder *pf)
>  
>  	/* If this is based on frame buffer, set the offset */
>  	if (op->atom == DW_OP_fbreg) {
> -		if (pf->fb_ops == NULL)
> -			die("The attribute of frame base is not supported.\n");
> +		if (pf->fb_ops == NULL) {
> +			pr_warning("The attribute of frame base is not "
> +				   "supported.\n");
> +			return -ENOTSUP;
> +		}
>  		ref = true;
>  		offs = op->number;
>  		op = &pf->fb_ops[0];
> @@ -419,50 +410,63 @@ static void convert_location(Dwarf_Op *op, struct probe_finder *pf)
>  		ref = true;
>  	} else if (op->atom == DW_OP_regx) {
>  		regn = op->number;
> -	} else
> -		die("DW_OP %d is not supported.", op->atom);
> +	} else {
> +		pr_warning("DW_OP %d is not supported.\n", op->atom);
> +		return -ENOTSUP;
> +	}
>  
>  	regs = get_arch_regstr(regn);
> -	if (!regs)
> -		die("%u exceeds max register number.", regn);
> +	if (!regs) {
> +		pr_warning("%u exceeds max register number.\n", regn);
> +		return -ERANGE;
> +	}
>  
>  	tvar->value = xstrdup(regs);
>  	if (ref) {
>  		tvar->ref = xzalloc(sizeof(struct kprobe_trace_arg_ref));
>  		tvar->ref->offset = (long)offs;
>  	}
> +	return 0;
>  }
>  
> -static void convert_variable_type(Dwarf_Die *vr_die,
> -				  struct kprobe_trace_arg *targ)
> +static int convert_variable_type(Dwarf_Die *vr_die,
> +				 struct kprobe_trace_arg *targ)
>  {
>  	Dwarf_Die type;
>  	char buf[16];
>  	int ret;
>  
> -	if (die_get_real_type(vr_die, &type) == NULL)
> -		die("Failed to get a type information of %s.",
> -		    dwarf_diename(vr_die));
> +	if (die_get_real_type(vr_die, &type) == NULL) {
> +		pr_warning("Failed to get a type information of %s.\n",
> +			   dwarf_diename(vr_die));
> +		return -ENOENT;
> +	}
>  
>  	ret = die_get_byte_size(&type) * 8;
>  	if (ret) {
>  		/* Check the bitwidth */
>  		if (ret > MAX_BASIC_TYPE_BITS) {
> -			pr_warning("  Warning: %s exceeds max-bitwidth."
> -				   " Cut down to %d bits.\n",
> -				   dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
> +			pr_info("%s exceeds max-bitwidth."
> +				" Cut down to %d bits.\n",
> +				dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
>  			ret = MAX_BASIC_TYPE_BITS;
>  		}
>  
>  		ret = snprintf(buf, 16, "%c%d",
>  			       die_is_signed_type(&type) ? 's' : 'u', ret);
> -		if (ret < 0 || ret >= 16)
> -			die("Failed to convert variable type.");
> +		if (ret < 0 || ret >= 16) {
> +			if (ret >= 16)
> +				ret = -E2BIG;
> +			pr_warning("Failed to convert variable type: %s\n",
> +				   strerror(-ret));
> +			return ret;
> +		}
>  		targ->type = xstrdup(buf);
>  	}
> +	return 0;
>  }
>  
> -static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
> +static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
>  				    struct perf_probe_arg_field *field,
>  				    struct kprobe_trace_arg_ref **ref_ptr,
>  				    Dwarf_Die *die_mem)
> @@ -473,21 +477,28 @@ static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
>  	Dwarf_Word offs;
>  
>  	pr_debug("converting %s in %s\n", field->name, varname);
> -	if (die_get_real_type(vr_die, &type) == NULL)
> -		die("Failed to get a type information of %s.", varname);
> +	if (die_get_real_type(vr_die, &type) == NULL) {
> +		pr_warning("Failed to get the type of %s.\n", varname);
> +		return -ENOENT;
> +	}
>  
>  	/* Check the pointer and dereference */
>  	if (dwarf_tag(&type) == DW_TAG_pointer_type) {
> -		if (!field->ref)
> -			die("Semantic error: %s must be referred by '->'",
> -			    field->name);
> +		if (!field->ref) {
> +			pr_err("Semantic error: %s must be referred by '->'\n",
> +			       field->name);
> +			return -EINVAL;
> +		}
>  		/* Get the type pointed by this pointer */
> -		if (die_get_real_type(&type, &type) == NULL)
> -			die("Failed to get a type information of %s.", varname);
> -
> +		if (die_get_real_type(&type, &type) == NULL) {
> +			pr_warning("Failed to get the type of %s.\n", varname);
> +			return -ENOENT;
> +		}
>  		/* Verify it is a data structure  */
> -		if (dwarf_tag(&type) != DW_TAG_structure_type)
> -			die("%s is not a data structure.", varname);
> +		if (dwarf_tag(&type) != DW_TAG_structure_type) {
> +			pr_warning("%s is not a data structure.\n", varname);
> +			return -EINVAL;
> +		}
>  
>  		ref = xzalloc(sizeof(struct kprobe_trace_arg_ref));
>  		if (*ref_ptr)
> @@ -496,34 +507,46 @@ static void convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
>  			*ref_ptr = ref;
>  	} else {
>  		/* Verify it is a data structure  */
> -		if (dwarf_tag(&type) != DW_TAG_structure_type)
> -			die("%s is not a data structure.", varname);
> -
> -		if (field->ref)
> -			die("Semantic error: %s must be referred by '.'",
> -			    field->name);
> -		if (!ref)
> -			die("Structure on a register is not supported yet.");
> +		if (dwarf_tag(&type) != DW_TAG_structure_type) {
> +			pr_warning("%s is not a data structure.\n", varname);
> +			return -EINVAL;
> +		}
> +		if (field->ref) {
> +			pr_err("Semantic error: %s must be referred by '.'\n",
> +			       field->name);
> +			return -EINVAL;
> +		}
> +		if (!ref) {
> +			pr_warning("Structure on a register is not "
> +				   "supported yet.\n");
> +			return -ENOTSUP;
> +		}
>  	}
>  
> -	if (die_find_member(&type, field->name, die_mem) == NULL)
> -		die("%s(tyep:%s) has no member %s.", varname,
> -		    dwarf_diename(&type), field->name);
> +	if (die_find_member(&type, field->name, die_mem) == NULL) {
> +		pr_warning("%s(tyep:%s) has no member %s.\n", varname,
> +			   dwarf_diename(&type), field->name);
> +		return -EINVAL;
> +	}
>  
>  	/* Get the offset of the field */
>  	if (dwarf_attr(die_mem, DW_AT_data_member_location, &attr) == NULL ||
> -	    dwarf_formudata(&attr, &offs) != 0)
> -		die("Failed to get the offset of %s.", field->name);
> +	    dwarf_formudata(&attr, &offs) != 0) {
> +		pr_warning("Failed to get the offset of %s.\n", field->name);
> +		return -ENOENT;
> +	}
>  	ref->offset += (long)offs;
>  
>  	/* Converting next field */
>  	if (field->next)
> -		convert_variable_fields(die_mem, field->name, field->next,
> -					&ref, die_mem);
> +		return convert_variable_fields(die_mem, field->name,
> +					       field->next, &ref, die_mem);
> +	else
> +		return 0;
>  }
>  
>  /* Show a variables in kprobe event format */
> -static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
> +static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
>  {
>  	Dwarf_Attribute attr;
>  	Dwarf_Die die_mem;
> @@ -538,28 +561,30 @@ static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
>  	if (ret <= 0 || nexpr == 0)
>  		goto error;
>  
> -	convert_location(expr, pf);
> -
> -	if (pf->pvar->field) {
> -		convert_variable_fields(vr_die, pf->pvar->var,
> -					pf->pvar->field, &pf->tvar->ref,
> -					&die_mem);
> +	ret = convert_location(expr, pf);
> +	if (ret == 0 && pf->pvar->field) {
> +		ret = convert_variable_fields(vr_die, pf->pvar->var,
> +					      pf->pvar->field, &pf->tvar->ref,
> +					      &die_mem);
>  		vr_die = &die_mem;
>  	}
> -	if (pf->pvar->type)
> -		pf->tvar->type = xstrdup(pf->pvar->type);
> -	else
> -		convert_variable_type(vr_die, pf->tvar);
> +	if (ret == 0) {
> +		if (pf->pvar->type)
> +			pf->tvar->type = xstrdup(pf->pvar->type);
> +		else
> +			ret = convert_variable_type(vr_die, pf->tvar);
> +	}
>  	/* *expr will be cached in libdw. Don't free it. */
> -	return ;
> +	return ret;
>  error:
>  	/* TODO: Support const_value */
> -	die("Failed to find the location of %s at this address.\n"
> -	    " Perhaps, it has been optimized out.", pf->pvar->var);
> +	pr_err("Failed to find the location of %s at this address.\n"
> +	       " Perhaps, it has been optimized out.\n", pf->pvar->var);
> +	return -ENOENT;
>  }
>  
>  /* Find a variable in a subprogram die */
> -static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
> +static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
>  {
>  	Dwarf_Die vr_die;
>  	char buf[32], *ptr;
> @@ -578,19 +603,22 @@ static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
>  	if (!is_c_varname(pf->pvar->var)) {
>  		/* Copy raw parameters */
>  		pf->tvar->value = xstrdup(pf->pvar->var);
> -	} else {
> -		pr_debug("Searching '%s' variable in context.\n",
> -			 pf->pvar->var);
> -		/* Search child die for local variables and parameters. */
> -		if (!die_find_variable(sp_die, pf->pvar->var, &vr_die))
> -			die("Failed to find '%s' in this function.",
> -			    pf->pvar->var);
> -		convert_variable(&vr_die, pf);
> +		return 0;
>  	}
> +
> +	pr_debug("Searching '%s' variable in context.\n",
> +		 pf->pvar->var);
> +	/* Search child die for local variables and parameters. */
> +	if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) {
> +		pr_warning("Failed to find '%s' in this function.\n",
> +			   pf->pvar->var);
> +		return -ENOENT;
> +	}
> +	return convert_variable(&vr_die, pf);
>  }
>  
>  /* Show a probe point to output buffer */
> -static void convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
> +static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
>  {
>  	struct kprobe_trace_event *tev;
>  	Dwarf_Addr eaddr;
> @@ -600,22 +628,31 @@ static void convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
>  	Dwarf_Attribute fb_attr;
>  	size_t nops;
>  
> -	if (pf->ntevs == MAX_PROBES)
> -		die("Too many( > %d) probe point found.\n", MAX_PROBES);
> +	if (pf->ntevs == MAX_PROBES) {
> +		pr_warning("Too many( > %d) probe point found.\n", MAX_PROBES);
> +		return -ERANGE;
> +	}
>  	tev = &pf->tevs[pf->ntevs++];
>  
>  	/* If no real subprogram, find a real one */
>  	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
>  		sp_die = die_find_real_subprogram(&pf->cu_die,
>  						 pf->addr, &die_mem);
> -		if (!sp_die)
> -			die("Probe point is not found in subprograms.");
> +		if (!sp_die) {
> +			pr_warning("Failed to find probe point in any "
> +				   "functions.\n");
> +			return -ENOENT;
> +		}
>  	}
>  
>  	/* Copy the name of probe point */
>  	name = dwarf_diename(sp_die);
>  	if (name) {
> -		dwarf_entrypc(sp_die, &eaddr);
> +		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
> +			pr_warning("Failed to get entry pc of %s\n",
> +				   dwarf_diename(sp_die));
> +			return -ENOENT;
> +		}
>  		tev->point.symbol = xstrdup(name);
>  		tev->point.offset = (unsigned long)(pf->addr - eaddr);
>  	} else
> @@ -633,9 +670,12 @@ static void convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
>  	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
>  		   pf->cfi != NULL) {
>  		Dwarf_Frame *frame;
> -		ret = dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame);
> -		DIE_IF(ret != 0);
> -		dwarf_frame_cfa(frame, &pf->fb_ops, &nops);
> +		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
> +		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
> +			pr_warning("Failed to get CFA on 0x%jx\n",
> +				   (uintmax_t)pf->addr);
> +			return -ENOENT;
> +		}
>  	}
>  
>  	/* Find each argument */
> @@ -644,45 +684,53 @@ static void convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
>  	for (i = 0; i < pf->pev->nargs; i++) {
>  		pf->pvar = &pf->pev->args[i];
>  		pf->tvar = &tev->args[i];
> -		find_variable(sp_die, pf);
> +		ret = find_variable(sp_die, pf);
> +		if (ret != 0)
> +			return ret;
>  	}
>  
>  	/* *pf->fb_ops will be cached in libdw. Don't free it. */
>  	pf->fb_ops = NULL;
> +	return 0;
>  }
>  
>  /* Find probe point from its line number */
> -static void find_probe_point_by_line(struct probe_finder *pf)
> +static int find_probe_point_by_line(struct probe_finder *pf)
>  {
>  	Dwarf_Lines *lines;
>  	Dwarf_Line *line;
>  	size_t nlines, i;
>  	Dwarf_Addr addr;
>  	int lineno;
> -	int ret;
> +	int ret = 0;
>  
> -	ret = dwarf_getsrclines(&pf->cu_die, &lines, &nlines);
> -	DIE_IF(ret != 0);
> +	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
> +		pr_warning("No source lines found in this CU.\n");
> +		return -ENOENT;
> +	}
>  
> -	for (i = 0; i < nlines; i++) {
> +	for (i = 0; i < nlines && ret == 0; i++) {
>  		line = dwarf_onesrcline(lines, i);
> -		dwarf_lineno(line, &lineno);
> -		if (lineno != pf->lno)
> +		if (dwarf_lineno(line, &lineno) != 0 ||
> +		    lineno != pf->lno)
>  			continue;
>  
>  		/* TODO: Get fileno from line, but how? */
>  		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
>  			continue;
>  
> -		ret = dwarf_lineaddr(line, &addr);
> -		DIE_IF(ret != 0);
> +		if (dwarf_lineaddr(line, &addr) != 0) {
> +			pr_warning("Failed to get the address of the line.\n");
> +			return -ENOENT;
> +		}
>  		pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
>  			 (int)i, lineno, (uintmax_t)addr);
>  		pf->addr = addr;
>  
> -		convert_probe_point(NULL, pf);
> +		ret = convert_probe_point(NULL, pf);
>  		/* Continuing, because target line might be inlined. */
>  	}
> +	return ret;
>  }
>  
>  /* Find lines which match lazy pattern */
> @@ -690,15 +738,27 @@ static int find_lazy_match_lines(struct list_head *head,
>  				 const char *fname, const char *pat)
>  {
>  	char *fbuf, *p1, *p2;
> -	int fd, line, nlines = 0;
> +	int fd, ret, line, nlines = 0;
>  	struct stat st;
>  
>  	fd = open(fname, O_RDONLY);
> -	if (fd < 0)
> -		die("failed to open %s", fname);
> -	DIE_IF(fstat(fd, &st) < 0);
> +	if (fd < 0) {
> +		pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
> +		return fd;
> +	}
> +
> +	ret = fstat(fd, &st);
> +	if (ret < 0) {
> +		pr_warning("Failed to get the size of %s: %s\n",
> +			   fname, strerror(errno));
> +		return ret;
> +	}
>  	fbuf = xmalloc(st.st_size + 2);
> -	DIE_IF(read(fd, fbuf, st.st_size) < 0);
> +	ret = read(fd, fbuf, st.st_size);
> +	if (ret < 0) {
> +		pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
> +		return ret;
> +	}
>  	close(fd);
>  	fbuf[st.st_size] = '\n';	/* Dummy line */
>  	fbuf[st.st_size + 1] = '\0';
> @@ -718,7 +778,7 @@ static int find_lazy_match_lines(struct list_head *head,
>  }
>  
>  /* Find probe points from lazy pattern  */
> -static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
> +static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
>  {
>  	Dwarf_Lines *lines;
>  	Dwarf_Line *line;
> @@ -726,31 +786,40 @@ static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
>  	Dwarf_Addr addr;
>  	Dwarf_Die die_mem;
>  	int lineno;
> -	int ret;
> +	int ret = 0;
>  
>  	if (list_empty(&pf->lcache)) {
>  		/* Matching lazy line pattern */
>  		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
>  					    pf->pev->point.lazy_line);
> -		if (ret <= 0)
> -			die("No matched lines found in %s.", pf->fname);
> +		if (ret == 0) {
> +			pr_debug("No matched lines found in %s.\n", pf->fname);
> +			return 0;
> +		} else if (ret < 0)
> +			return ret;
>  	}
>  
> -	ret = dwarf_getsrclines(&pf->cu_die, &lines, &nlines);
> -	DIE_IF(ret != 0);
> -	for (i = 0; i < nlines; i++) {
> +	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
> +		pr_warning("No source lines found in this CU.\n");
> +		return -ENOENT;
> +	}
> +
> +	for (i = 0; i < nlines && ret >= 0; i++) {
>  		line = dwarf_onesrcline(lines, i);
>  
> -		dwarf_lineno(line, &lineno);
> -		if (!line_list__has_line(&pf->lcache, lineno))
> +		if (dwarf_lineno(line, &lineno) != 0 ||
> +		    !line_list__has_line(&pf->lcache, lineno))
>  			continue;
>  
>  		/* TODO: Get fileno from line, but how? */
>  		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
>  			continue;
>  
> -		ret = dwarf_lineaddr(line, &addr);
> -		DIE_IF(ret != 0);
> +		if (dwarf_lineaddr(line, &addr) != 0) {
> +			pr_debug("Failed to get the address of line %d.\n",
> +				 lineno);
> +			continue;
> +		}
>  		if (sp_die) {
>  			/* Address filtering 1: does sp_die include addr? */
>  			if (!dwarf_haspc(sp_die, addr))
> @@ -764,27 +833,42 @@ static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
>  			 (int)i, lineno, (unsigned long long)addr);
>  		pf->addr = addr;
>  
> -		convert_probe_point(sp_die, pf);
> +		ret = convert_probe_point(sp_die, pf);
>  		/* Continuing, because target line might be inlined. */
>  	}
>  	/* TODO: deallocate lines, but how? */
> +	return ret;
>  }
>  
> +/* Callback parameter with return value */
> +struct dwarf_callback_param {
> +	void *data;
> +	int retval;
> +};
> +
>  static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
>  {
> -	struct probe_finder *pf = (struct probe_finder *)data;
> +	struct dwarf_callback_param *param = data;
> +	struct probe_finder *pf = param->data;
>  	struct perf_probe_point *pp = &pf->pev->point;
> +	Dwarf_Addr addr;
>  
>  	if (pp->lazy_line)
> -		find_probe_point_lazy(in_die, pf);
> +		param->retval = find_probe_point_lazy(in_die, pf);
>  	else {
>  		/* Get probe address */
> -		pf->addr = die_get_entrypc(in_die);
> +		if (dwarf_entrypc(in_die, &addr) != 0) {
> +			pr_warning("Failed to get entry pc of %s.\n",
> +				   dwarf_diename(in_die));
> +			param->retval = -ENOENT;
> +			return DWARF_CB_ABORT;
> +		}
> +		pf->addr = addr;
>  		pf->addr += pp->offset;
>  		pr_debug("found inline addr: 0x%jx\n",
>  			 (uintmax_t)pf->addr);
>  
> -		convert_probe_point(in_die, pf);
> +		param->retval = convert_probe_point(in_die, pf);
>  	}
>  
>  	return DWARF_CB_OK;
> @@ -793,39 +877,53 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
>  /* Search function from function name */
>  static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
>  {
> -	struct probe_finder *pf = (struct probe_finder *)data;
> +	struct dwarf_callback_param *param = data;
> +	struct probe_finder *pf = param->data;
>  	struct perf_probe_point *pp = &pf->pev->point;
>  
>  	/* Check tag and diename */
>  	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
>  	    die_compare_name(sp_die, pp->function) != 0)
> -		return 0;
> +		return DWARF_CB_OK;
>  
>  	pf->fname = dwarf_decl_file(sp_die);
>  	if (pp->line) { /* Function relative line */
>  		dwarf_decl_line(sp_die, &pf->lno);
>  		pf->lno += pp->line;
> -		find_probe_point_by_line(pf);
> +		param->retval = find_probe_point_by_line(pf);
>  	} else if (!dwarf_func_inline(sp_die)) {
>  		/* Real function */
>  		if (pp->lazy_line)
> -			find_probe_point_lazy(sp_die, pf);
> +			param->retval = find_probe_point_lazy(sp_die, pf);
>  		else {
> -			pf->addr = die_get_entrypc(sp_die);
> +			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
> +				pr_warning("Failed to get entry pc of %s.\n",
> +					   dwarf_diename(sp_die));
> +				param->retval = -ENOENT;
> +				return DWARF_CB_ABORT;
> +			}
>  			pf->addr += pp->offset;
>  			/* TODO: Check the address in this function */
> -			convert_probe_point(sp_die, pf);
> +			param->retval = convert_probe_point(sp_die, pf);
>  		}
> -	} else
> +	} else {
> +		struct dwarf_callback_param _param = {.data = (void *)pf,
> +						      .retval = 0};
>  		/* Inlined function: search instances */
> -		dwarf_func_inline_instances(sp_die, probe_point_inline_cb, pf);
> +		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
> +					    &_param);
> +		param->retval = _param.retval;
> +	}
>  
> -	return 1; /* Exit; no same symbol in this CU. */
> +	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
>  }
>  
> -static void find_probe_point_by_func(struct probe_finder *pf)
> +static int find_probe_point_by_func(struct probe_finder *pf)
>  {
> -	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, pf, 0);
> +	struct dwarf_callback_param _param = {.data = (void *)pf,
> +					      .retval = 0};
> +	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
> +	return _param.retval;
>  }
>  
>  /* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
> @@ -838,14 +936,18 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
>  	size_t cuhl;
>  	Dwarf_Die *diep;
>  	Dwarf *dbg;
> +	int ret = 0;
>  
>  	pf.tevs = xzalloc(sizeof(struct kprobe_trace_event) * MAX_PROBES);
>  	*tevs = pf.tevs;
>  	pf.ntevs = 0;
>  
>  	dbg = dwarf_begin(fd, DWARF_C_READ);
> -	if (!dbg)
> -		return -ENOENT;
> +	if (!dbg) {
> +		pr_warning("No dwarf info found in the vmlinux - "
> +			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
> +		return -EBADF;
> +	}
>  
>  	/* Get the call frame information from this dwarf */
>  	pf.cfi = dwarf_getcfi(dbg);
> @@ -853,7 +955,8 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
>  	off = 0;
>  	line_list__init(&pf.lcache);
>  	/* Loop on CUs (Compilation Unit) */
> -	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
> +	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
> +	       ret >= 0) {
>  		/* Get the DIE(Debugging Information Entry) of this CU */
>  		diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
>  		if (!diep)
> @@ -867,12 +970,12 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
>  
>  		if (!pp->file || pf.fname) {
>  			if (pp->function)
> -				find_probe_point_by_func(&pf);
> +				ret = find_probe_point_by_func(&pf);
>  			else if (pp->lazy_line)
> -				find_probe_point_lazy(NULL, &pf);
> +				ret = find_probe_point_lazy(NULL, &pf);
>  			else {
>  				pf.lno = pp->line;
> -				find_probe_point_by_line(&pf);
> +				ret = find_probe_point_by_line(&pf);
>  			}
>  		}
>  		off = noff;
> @@ -880,7 +983,7 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
>  	line_list__free(&pf.lcache);
>  	dwarf_end(dbg);
>  
> -	return pf.ntevs;
> +	return (ret < 0) ? ret : pf.ntevs;
>  }
>  
>  /* Reverse search */
> @@ -893,10 +996,11 @@ int find_perf_probe_point(int fd, unsigned long addr,
>  	Dwarf_Addr laddr, eaddr;
>  	const char *tmp;
>  	int lineno, ret = 0;
> +	bool found = false;
>  
>  	dbg = dwarf_begin(fd, DWARF_C_READ);
>  	if (!dbg)
> -		return -ENOENT;
> +		return -EBADF;
>  
>  	/* Find cu die */
>  	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
> @@ -907,82 +1011,87 @@ int find_perf_probe_point(int fd, unsigned long addr,
>  	/* Find a corresponding line */
>  	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
>  	if (line) {
> -		dwarf_lineaddr(line, &laddr);
> -		if ((Dwarf_Addr)addr == laddr) {
> -			dwarf_lineno(line, &lineno);
> -			ppt->line = lineno;
> -
> +		if (dwarf_lineaddr(line, &laddr) == 0 &&
> +		    (Dwarf_Addr)addr == laddr &&
> +		    dwarf_lineno(line, &lineno) == 0) {
>  			tmp = dwarf_linesrc(line, NULL, NULL);
> -			DIE_IF(!tmp);
> -			ppt->file = xstrdup(tmp);
> -			ret = 1;
> +			if (tmp) {
> +				ppt->line = lineno;
> +				ppt->file = xstrdup(tmp);
> +				found = true;
> +			}
>  		}
>  	}
>  
>  	/* Find a corresponding function */
>  	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
>  		tmp = dwarf_diename(&spdie);
> -		if (!tmp)
> +		if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
>  			goto end;
>  
> -		dwarf_entrypc(&spdie, &eaddr);
> -		if (!lineno) {
> -			/* We don't have a line number, let's use offset */
> -			ppt->function = xstrdup(tmp);
> -			ppt->offset = addr - (unsigned long)eaddr;
> -			ret = 1;
> -			goto end;
> -		}
> -		if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr, &indie)) {
> -			/* addr in an inline function */
> -			tmp = dwarf_diename(&indie);
> -			if (!tmp)
> -				goto end;
> -			dwarf_decl_line(&indie, &lineno);
> -		} else {
> -			if (eaddr == addr)	/* No offset: function entry */
> -				lineno = ppt->line;
> -			else
> -				dwarf_decl_line(&spdie, &lineno);
> +		if (ppt->line) {
> +			if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
> +						&indie)) {
> +				/* addr in an inline function */
> +				tmp = dwarf_diename(&indie);
> +				if (!tmp)
> +					goto end;
> +				ret = dwarf_decl_line(&indie, &lineno);
> +			} else {
> +				if (eaddr == addr) {	/* Function entry */
> +					lineno = ppt->line;
> +					ret = 0;
> +				} else
> +					ret = dwarf_decl_line(&spdie, &lineno);
> +			}
> +			if (ret == 0) {
> +				/* Make a relative line number */
> +				ppt->line -= lineno;
> +				goto found;
> +			}
>  		}
> +		/* We don't have a line number, let's use offset */
> +		ppt->offset = addr - (unsigned long)eaddr;
> +found:
>  		ppt->function = xstrdup(tmp);
> -		ppt->line -= lineno;	/* Make a relative line number */
> +		found = true;
>  	}
>  
>  end:
>  	dwarf_end(dbg);
> +	if (ret >= 0)
> +		ret = found ? 1 : 0;
>  	return ret;
>  }
>  
>  
>  /* Find line range from its line number */
> -static void find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
> +static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
>  {
>  	Dwarf_Lines *lines;
>  	Dwarf_Line *line;
>  	size_t nlines, i;
>  	Dwarf_Addr addr;
>  	int lineno;
> -	int ret;
>  	const char *src;
>  	Dwarf_Die die_mem;
>  
>  	line_list__init(&lf->lr->line_list);
> -	ret = dwarf_getsrclines(&lf->cu_die, &lines, &nlines);
> -	DIE_IF(ret != 0);
> +	if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
> +		pr_warning("No source lines found in this CU.\n");
> +		return -ENOENT;
> +	}
>  
>  	for (i = 0; i < nlines; i++) {
>  		line = dwarf_onesrcline(lines, i);
> -		ret = dwarf_lineno(line, &lineno);
> -		DIE_IF(ret != 0);
> -		if (lf->lno_s > lineno || lf->lno_e < lineno)
> +		if (dwarf_lineno(line, &lineno) != 0 ||
> +		    (lf->lno_s > lineno || lf->lno_e < lineno))
>  			continue;
>  
>  		if (sp_die) {
>  			/* Address filtering 1: does sp_die include addr? */
> -			ret = dwarf_lineaddr(line, &addr);
> -			DIE_IF(ret != 0);
> -			if (!dwarf_haspc(sp_die, addr))
> +			if (dwarf_lineaddr(line, &addr) != 0 ||
> +			    !dwarf_haspc(sp_die, addr))
>  				continue;
>  
>  			/* Address filtering 2: No child include addr? */
> @@ -1007,18 +1116,22 @@ static void find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
>  		free(lf->lr->path);
>  		lf->lr->path = NULL;
>  	}
> +	return lf->found;
>  }
>  
>  static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
>  {
> -	find_line_range_by_line(in_die, (struct line_finder *)data);
> +	struct dwarf_callback_param *param = data;
> +
> +	param->retval = find_line_range_by_line(in_die, param->data);
>  	return DWARF_CB_ABORT;	/* No need to find other instances */
>  }
>  
>  /* Search function from function name */
>  static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
>  {
> -	struct line_finder *lf = (struct line_finder *)data;
> +	struct dwarf_callback_param *param = data;
> +	struct line_finder *lf = param->data;
>  	struct line_range *lr = lf->lr;
>  
>  	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
> @@ -1033,38 +1146,47 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
>  			lf->lno_e = lr->offset + lr->end;
>  		lr->start = lf->lno_s;
>  		lr->end = lf->lno_e;
> -		if (dwarf_func_inline(sp_die))
> +		if (dwarf_func_inline(sp_die)) {
> +			struct dwarf_callback_param _param;
> +			_param.data = (void *)lf;
> +			_param.retval = 0;
>  			dwarf_func_inline_instances(sp_die,
> -						    line_range_inline_cb, lf);
> -		else
> -			find_line_range_by_line(sp_die, lf);
> -		return 1;
> +						    line_range_inline_cb,
> +						    &_param);
> +			param->retval = _param.retval;
> +		} else
> +			param->retval = find_line_range_by_line(sp_die, lf);
> +		return DWARF_CB_ABORT;
>  	}
> -	return 0;
> +	return DWARF_CB_OK;
>  }
>  
> -static void find_line_range_by_func(struct line_finder *lf)
> +static int find_line_range_by_func(struct line_finder *lf)
>  {
> -	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, lf, 0);
> +	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
> +	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
> +	return param.retval;
>  }
>  
>  int find_line_range(int fd, struct line_range *lr)
>  {
>  	struct line_finder lf = {.lr = lr, .found = 0};
> -	int ret;
> +	int ret = 0;
>  	Dwarf_Off off = 0, noff;
>  	size_t cuhl;
>  	Dwarf_Die *diep;
>  	Dwarf *dbg;
>  
>  	dbg = dwarf_begin(fd, DWARF_C_READ);
> -	if (!dbg)
> -		return -ENOENT;
> +	if (!dbg) {
> +		pr_warning("No dwarf info found in the vmlinux - "
> +			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
> +		return -EBADF;
> +	}
>  
>  	/* Loop on CUs (Compilation Unit) */
> -	while (!lf.found) {
> -		ret = dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL);
> -		if (ret != 0)
> +	while (!lf.found && ret >= 0) {
> +		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
>  			break;
>  
>  		/* Get the DIE(Debugging Information Entry) of this CU */
> @@ -1080,20 +1202,21 @@ int find_line_range(int fd, struct line_range *lr)
>  
>  		if (!lr->file || lf.fname) {
>  			if (lr->function)
> -				find_line_range_by_func(&lf);
> +				ret = find_line_range_by_func(&lf);
>  			else {
>  				lf.lno_s = lr->start;
>  				if (!lr->end)
>  					lf.lno_e = INT_MAX;
>  				else
>  					lf.lno_e = lr->end;
> -				find_line_range_by_line(NULL, &lf);
> +				ret = find_line_range_by_line(NULL, &lf);
>  			}
>  		}
>  		off = noff;
>  	}
>  	pr_debug("path: %lx\n", (unsigned long)lr->path);
>  	dwarf_end(dbg);
> -	return lf.found;
> +
> +	return (ret < 0) ? ret : lf.found;
>  }
>  
> 
> 

-- 
Masami Hiramatsu
e-mail: mhiramat@redhat.com