[PATCH] [v2] bpf: make bpf_session_is_return() reference optional

[Arnd Bergmann]

From: Arnd Bergmann <arnd@xxxxxxxx>

Building without CONFIG_BPF_EVENTS produces a build-time
warning:

WARN: resolve_btfids: unresolved symbol bpf_session_is_return

The function is actually defined in kernel/trace/bpf_trace.o,
which is built conditionally based on configuration.

Make the reference to this function conditional as well,
as is already done in the bpf verifier for other functions.

Fixes: 8fe4dc4f6456 ("bpf: change prototype of bpf_session_{cookie,is_return}")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
v2: fix patch title
---
 kernel/bpf/verifier.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 03f9e16c2abe..a5139f45e366 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -10882,7 +10882,11 @@ BTF_ID(func, bpf_task_work_schedule_resume)
 BTF_ID(func, bpf_arena_alloc_pages)
 BTF_ID(func, bpf_arena_free_pages)
 BTF_ID(func, bpf_arena_reserve_pages)
+#ifdef CONFIG_BPF_EVENTS
 BTF_ID(func, bpf_session_is_return)
+#else
+BTF_ID_UNUSED
+#endif
 BTF_ID(func, bpf_stream_vprintk)
 BTF_ID(func, bpf_stream_print_stack)
 
-- 
2.39.5