[PATCH 6.18 014/752] perf annotate: Fix memcpy size in arch__grow_instructions()

Sasha Levin
2026-02-28T17:48:18Z

From: Suchit Karunakaran <suchitkarunakaran@gmail.com>

[ Upstream commit f0d98c78f8bf73ce2a9b7793f66cda240fa9ab10 ]

The memcpy() in arch__grow_instructions() is copying the wrong number of
bytes when growing from a non-allocated table.

It should copy arch->nr_instructions * sizeof(struct ins) bytes, not
just arch->nr_instructions bytes.

This bug causes data corruption as only a partial copy of the
instruction table is made, leading to garbage data in most entries and
potential crashes

Fixes: 2a1ff812c40be982 ("perf annotate: Introduce alternative method of keeping instructions table")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/disasm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 924429142631a..88706b98b9064 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -81,7 +81,7 @@ static int arch__grow_instructions(struct arch *arch)
if (new_instructions == NULL)
return -1;

- memcpy(new_instructions, arch->instructions, arch->nr_instructions);
+ memcpy(new_instructions, arch->instructions, arch->nr_instructions * sizeof(struct ins));
goto out_update_instructions;
}

--
2.51.0