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Message-ID: <20240816235840.2754937-2-namhyung@kernel.org>
Date: Fri, 16 Aug 2024 16:58:31 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Kan Liang <kan.liang@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-perf-users@...r.kernel.org,
Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
Masami Hiramatsu <mhiramat@...nel.org>
Subject: [PATCH 1/9] 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: 932dcc2c39ae ("perf dwarf-aux: Add die_collect_vars()")
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/util/dwarf-aux.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 5e080d7e22c2..beb632153a74 100644
--- 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;
--
2.46.0.184.g6999bdac58-goog
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