It seems BPF CO-RE reloc doesn't work well with the pattern that gets
the field-offset only. Use offsetof() to make it explicit so that
the compiler would generate the correct code.
Fixes: 0c1228486bef ("perf lock contention: Support pre-5.14 kernels")
Co-developed-by: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/util/bpf_skel/lock_contention.bpf.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index 30c193078bdb..8d3cfbb3cc65 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -429,21 +429,21 @@ struct rq___new {
SEC("raw_tp/bpf_test_finish")
int BPF_PROG(collect_lock_syms)
{
- __u64 lock_addr;
+ __u64 lock_addr, lock_off;
__u32 lock_flag;
+ if (bpf_core_field_exists(struct rq___new, __lock))
+ lock_off = offsetof(struct rq___new, __lock);
+ else
+ lock_off = offsetof(struct rq___old, lock);
+
for (int i = 0; i < MAX_CPUS; i++) {
struct rq *rq = bpf_per_cpu_ptr(&runqueues, i);
- struct rq___new *rq_new = (void *)rq;
- struct rq___old *rq_old = (void *)rq;
if (rq == NULL)
break;
- if (bpf_core_field_exists(rq_new->__lock))
- lock_addr = (__u64)&rq_new->__lock;
- else
- lock_addr = (__u64)&rq_old->lock;
+ lock_addr = (__u64)(void *)rq + lock_off;
lock_flag = LOCK_CLASS_RQLOCK;
bpf_map_update_elem(&lock_syms, &lock_addr, &lock_flag, BPF_ANY);
}
--
2.40.1.495.gc816e09b53d-goog
