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perf dwarf-aux: Fix libdw API contract violations

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Check return values of `dwarf_decl_line` (where non-optional),
`dwarf_getfuncs`, and `dwarf_lineaddr` to prevent using uninitialized
stack variables or incorrectly reporting success on failure.

For the root DIE in `die_walk_lines()`, `dwarf_decl_line` and
`die_get_decl_file` are optional and their failures are handled
gracefully to avoid breaking line walking on valid functions.
Specifically, remove the strict `!decf` (declared file) check that
would prematurely abort line walking on generated or artificial
functions lacking this optional attribute.

Additionally:
 - Add NULL pointer protection for `strcmp()` in `die_walk_lines()`
   when `inf` or `decf` are NULL to prevent crashes on generated
   code.
 - Use `dwarf_attr_integrate` in `die_get_data_member_location` to
   correctly resolve inherited member locations (e.g. via abstract
   origin or specification).

Fixes: 57f95bf5f8 ("perf probe: Show correct statement line number by perf probe -l")
Fixes: 3f4460a28f ("perf probe: Filter out redundant inline-instances")
Fixes: 75186a9b09 ("perf probe: Fix to show lines of sys_ functions correctly")
Fixes: e0d153c690 ("perf-probe: Move dwarf library routines to dwarf-aux.{c, h}")
Fixes: 6243b9dc4c ("perf probe: Move dwarf specific functions to dwarf-aux.c")
Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zecheng Li <zli94@ncsu.edu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2026-05-04 01:12:20 -07:00 committed by Arnaldo Carvalho de Melo
parent d37a546770
commit 17e9b4243e
2 changed files with 22 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
tools/perf/util/dwarf-aux.c
View File

@ -125,7 +125,8 @@ int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr,
&& die_entrypc(&die_mem, &faddr) == 0 &&
faddr == addr) {
*fname = die_get_decl_file(&die_mem);
dwarf_decl_line(&die_mem, lineno);
if (dwarf_decl_line(&die_mem, lineno) != 0)
return -ENOENT;
goto out;
}
@ -459,7 +460,7 @@ int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
size_t nexpr;
int ret;
if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
if (dwarf_attr_integrate(mb_die, DW_AT_data_member_location, &attr) == NULL)
return -ENOENT;
if (dwarf_formudata(&attr, offs) != 0) {
@ -795,8 +796,7 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
/* Ignore redundant instances */
if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
dwarf_decl_line(origin, &tmp);
if (die_get_call_lineno(inst) == tmp) {
if (dwarf_decl_line(origin, &tmp) == 0 && die_get_call_lineno(inst) == tmp) {
tmp = die_get_decl_fileno(origin);
if (die_get_call_fileno(inst) == tmp)
return DIE_FIND_CB_CONTINUE;
@ -950,11 +950,6 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
dwarf_decl_line(rt_die, &decl);
decf = die_get_decl_file(rt_die);
if (!decf) {
pr_debug2("Failed to get the declared file name of %s\n",
dwarf_diename(rt_die));
return -EINVAL;
}
} else
cu_die = rt_die;
if (!cu_die) {
@ -998,11 +993,12 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
/* Call-site check */
inf = die_get_call_file(&die_mem);
if ((inf && !strcmp(inf, decf)) &&
if ((inf == decf || (inf && decf && !strcmp(inf, decf))) &&
die_get_call_lineno(&die_mem) == lineno)
goto found;
dwarf_decl_line(&die_mem, &inl);
if (dwarf_decl_line(&die_mem, &inl) != 0)
inl = 0;
if (inl != decl ||
decf != die_get_decl_file(&die_mem))
continue;
@ -1034,8 +1030,10 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
.data = data,
.retval = 0,
};
dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
ret = param.retval;
if (dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0) < 0)
ret = -EINVAL;
else
ret = param.retval;
}
return ret;
@ -1939,10 +1937,12 @@ static bool die_get_postprologue_addr(unsigned long entrypc_idx,
break;
}
dwarf_lineaddr(line, postprologue_addr);
if (*postprologue_addr >= highpc)
dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
postprologue_addr);
if (dwarf_lineaddr(line, postprologue_addr) != 0)
return false;
if (*postprologue_addr >= highpc) {
if (dwarf_lineaddr(dwarf_onesrcline(lines, i - 1), postprologue_addr) != 0)
return false;
}
return true;
}

5
tools/perf/util/dwarf-aux.h
View File

@ -10,6 +10,11 @@
#include <elfutils/libdwfl.h>
#include <elfutils/version.h>
static inline const char *die_name(Dwarf_Die *die)
{
return dwarf_diename(die) ?: "<unknown>";
}
struct strbuf;
/* Find the realpath of the target file */