This is a note to let you know that I've just added the patch titled
perf dwarf-aux: Check allowed location expressions when collecting variables
to the 6.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-dwarf-aux-check-allowed-location-expressions-wh.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d7b641a84475a10c013c6097ef80e982040836a7
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
Date: Fri Aug 16 16:58:31 2024 -0700
perf dwarf-aux: Check allowed location expressions when collecting variables
[ Upstream commit e8bb03ed6850c6ed4ce2f1600ea73401fc2ebd95 ]
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@xxxxxxxxxx>
Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240816235840.2754937-2-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 44ef968a7ad33..e7de5045c43a7 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;
