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authorJiri Olsa <jolsa@kernel.org>2023-05-10 15:51:31 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2023-05-10 16:15:04 -0300
commit760ebc45746b498a36332acefd9e2838a3f8fcf0 (patch)
tree2a524447dcc6b8eea344423c36bcd5b7a212d56d /tools/perf
parentbfd431cb2c68cbaec7a27b8a979d031f8501301b (diff)
downloadlwn-760ebc45746b498a36332acefd9e2838a3f8fcf0.tar.gz
lwn-760ebc45746b498a36332acefd9e2838a3f8fcf0.zip
perf lock contention: Add empty 'struct rq' to satisfy libbpf 'runqueue' type verification
If 'struct rq' isn't defined in lock_contention.bpf.c then the type for the 'runqueue' variable ends up being a forward declaration (BTF_KIND_FWD) while the kernel has it defined (BTF_KIND_STRUCT). This makes libbpf decide it has incompatible types and then fails to load the BPF skeleton: # perf lock con -ab sleep 1 libbpf: extern (var ksym) 'runqueues': incompatible types, expected [95] fwd rq, but kernel has [55509] struct rq libbpf: failed to load object 'lock_contention_bpf' libbpf: failed to load BPF skeleton 'lock_contention_bpf': -22 Failed to load lock-contention BPF skeleton lock contention BPF setup failed # Add it as an empty struct to satisfy that type verification: # perf lock con -ab sleep 1 contended total wait max wait avg wait type caller 2 50.64 us 25.38 us 25.32 us spinlock tick_do_update_jiffies64+0x25 1 26.18 us 26.18 us 26.18 us spinlock tick_do_update_jiffies64+0x25 # Committer notes: Extracted from a larger patch as Namhyung had already fixed the other issues in e53de7b65a3ca59a ("perf lock contention: Fix struct rq lock access"). Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Changbin Du <changbin.du@huawei.com> Cc: Hao Luo <haoluo@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Yang Jihong <yangjihong1@huawei.com> Link: https://lore.kernel.org/lkml/ZFVqeKLssg7uzxzI@krava Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/bpf_skel/lock_contention.bpf.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index 8d3cfbb3cc65..1d48226ae75d 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -416,6 +416,8 @@ int contention_end(u64 *ctx)
return 0;
}
+struct rq {};
+
extern struct rq runqueues __ksym;
struct rq___old {