[PATCH 4/4] selftests/bpf: Add selftests for stream functions under lock

[Emil Tsalapatis <emil@etsalapatis.com>]

Add a selftest to ensure BPF stream functions can now be called
while holding a lock.

Signed-off-by: Emil Tsalapatis (Meta) <emil@etsalapatis.com>
---
 tools/testing/selftests/bpf/progs/stream.c | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/stream.c b/tools/testing/selftests/bpf/progs/stream.c
index f63b378de090..6f999ba951a3 100644
--- a/tools/testing/selftests/bpf/progs/stream.c
+++ b/tools/testing/selftests/bpf/progs/stream.c
@@ -42,6 +42,10 @@ int size;
 u64 fault_addr;
 void *arena_ptr;
 
+#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8)))
+
+private(STREAM) struct bpf_spin_lock block;
+
 SEC("syscall")
 __success __retval(0)
 int stream_exhaust(void *ctx)
@@ -255,4 +259,32 @@ int stream_print_stack_invalid_id(void *ctx)
 	return bpf_stream_print_stack((enum bpf_stream_id)0xbadcafe);
 }
 
+SEC("syscall")
+__arch_x86_64
+__arch_arm64
+__success __retval(0)
+__stdout(_STR)
+__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
+__stderr("Call trace:\n"
+"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
+"|[ \t]+[^\n]+\n)*}}")
+int stream_print_kfuncs_locked(void *ctx)
+{
+	int ret;
+
+	bpf_spin_lock(&block);
+
+	ret = bpf_stream_printk(BPF_STDOUT, _STR);
+	if (ret)
+		goto out;
+
+	ret = bpf_stream_print_stack(BPF_STDERR);
+
+out:
+	bpf_spin_unlock(&block);
+
+	return ret;
+}
+
+
 char _license[] SEC("license") = "GPL";
-- 
2.49.0