perf_clear_branch_entry_bitfields() zeroes individual bitfields of struct perf_branch_entry but misses the new_type (4 bits) and priv (3 bits) fields. This means any code path that relies on this function to produce a clean entry may expose stale or uninitialised data in these fields to userspace. The function was introduced by commit bfe4daf850f4 ("perf/core: Add perf_clear_branch_entry_bitfields() helper") specifically to "centralize the initialization to avoid missing a field in case more are added." Unfortunately, the commits that later added new_type and priv to struct perf_branch_entry only updated the UAPI header and did not update this clearing function. Zero new_type and priv alongside the other bitfields. Fixes: b190bc4ac9e6 ("perf: Extend branch type classification") Fixes: 5402d25aa571 ("perf: Capture branch privilege information") Signed-off-by: Puranjay Mohan --- include/linux/perf_event.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 48d851fbd8ea..d7f39b7e9cda 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1481,6 +1481,8 @@ static inline void perf_clear_branch_entry_bitfields(struct perf_branch_entry *b br->cycles = 0; br->type = 0; br->spec = PERF_BR_SPEC_NA; + br->new_type = 0; + br->priv = 0; br->reserved = 0; } -- 2.52.0