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perf dwarf-aux: Use signed variable types in match_var_offset 

match_var_offset() compares address offsets to determine if an access
falls within a variable's bounds. The offsets involved for those
relative to base registers from DW_OP_breg can be negative.

The current implementation uses unsigned types (u64) for these offsets,
which rejects almost all negative values.

Change the signature of match_var_offset() to use signed types (s64).

This ensures correct behavior when addr_offset or addr_type are
negative.

Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Zecheng Li <zecheng@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xu Liu <xliuprof@google.com>
Link: https://lore.kernel.org/r/20250825195412.223077-2-zecheng@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Zecheng Li 2025-08-25 19:54:03 +00:00 committed by Arnaldo Carvalho de Melo
parent 9105df0185
commit 414bf79deb
1 changed files with 6 additions and 5 deletions
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11
tools/perf/util/dwarf-aux.c
View File

@ -1388,18 +1388,19 @@ struct find_var_data {
#define DWARF_OP_DIRECT_REGS 32
static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data,
u64 addr_offset, u64 addr_type, bool is_pointer)
s64 addr_offset, s64 addr_type, bool is_pointer)
{
Dwarf_Die type_die;
Dwarf_Word size;
s64 offset = addr_offset - addr_type;
if (addr_offset == addr_type) {
if (offset == 0) {
/* Update offset relative to the start of the variable */
data->offset = 0;
return true;
}
if (addr_offset < addr_type)
if (offset < 0)
return false;
if (die_get_real_type(die_mem, &type_die) == NULL)
@ -1414,11 +1415,11 @@ static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data,
if (dwarf_aggregate_size(&type_die, &size) < 0)
return false;
if (addr_offset >= addr_type + size)
if ((u64)offset >= size)
return false;
/* Update offset relative to the start of the variable */
data->offset = addr_offset - addr_type;
data->offset = offset;
return true;
}