perf dwarf-aux: Check allowed location expressions when collecting variables

It missed to call check_allowed_ops() in __die_collect_vars_cb() so it
can take variables with complex location expression incorrectly.

For example, I found some variable has this expression.

    015d8df8 ffffffff81aacfb3 (base address)
    015d8e01 v000000000000004 v000000000000000 views at 015d8df2 for:
             ffffffff81aacfb3 ffffffff81aacfd2 (DW_OP_fbreg: -176; DW_OP_deref;
						DW_OP_plus_uconst: 332; DW_OP_deref_size: 4;
						DW_OP_lit1; DW_OP_shra; DW_OP_const1u: 64;
						DW_OP_minus; DW_OP_stack_value)
    015d8e14 v000000000000000 v000000000000000 views at 015d8df4 for:
             ffffffff81aacfd2 ffffffff81aacfd7 (DW_OP_reg3 (rbx))
    015d8e19 v000000000000000 v000000000000000 views at 015d8df6 for:
             ffffffff81aacfd7 ffffffff81aad020 (DW_OP_fbreg: -176; DW_OP_deref;
						DW_OP_plus_uconst: 332; DW_OP_deref_size: 4;
						DW_OP_lit1; DW_OP_shra; DW_OP_const1u: 64;
						DW_OP_minus; DW_OP_stack_value)
    015d8e2c <End of list>

It looks like '((int *)(-176(%rbp) + 332) >> 1) - 64' but the current
code thought it's just -176(%rbp) and processed the variable incorrectly.
It should reject such a complex expression if check_allowed_ops()
doesn't like it. :)

Fixes: 932dcc2c39aedf54 ("perf dwarf-aux: Add die_collect_vars()")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240816235840.2754937-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 5e080d7e22c2a7886f6052eb335af965a45d49f9..beb632153a7441605c313beccfeff55e96a4c945 100644 (file)
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -1598,6 +1598,9 @@ static int __die_collect_vars_cb(Dwarf_Die *die_mem, void *arg)
        if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0)
                return DIE_FIND_CB_SIBLING;
 
+       if (!check_allowed_ops(ops, nops))
+               return DIE_FIND_CB_SIBLING;
+
        if (die_get_real_type(die_mem, &type_die) == NULL)
                return DIE_FIND_CB_SIBLING;