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authorAlexei Starovoitov <ast@kernel.org>2019-08-02 16:23:40 -0700
committerAlexei Starovoitov <ast@kernel.org>2019-08-06 08:20:31 -0700
commit8c30396074c131765b19eb3cb7ff764a4f2f2913 (patch)
tree46e44350fd17175e1ab9b8394c980c6e6fe89300
parentselftests/bpf: add loop test 4 (diff)
downloadlinux-dev-8c30396074c131765b19eb3cb7ff764a4f2f2913.tar.xz
linux-dev-8c30396074c131765b19eb3cb7ff764a4f2f2913.zip
selftests/bpf: add loop test 5
Add a test with multiple exit conditions. It's not an infinite loop only when the verifier can properly track all math on variable 'i' through all possible ways of executing this loop. barrier()s are needed to disable llvm optimization that combines multiple branches into fewer branches. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com>
-rw-r--r--tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c1
-rw-r--r--tools/testing/selftests/bpf/progs/loop5.c32
2 files changed, 33 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
index e9e72d8d7aae..0caf8eafa9eb 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
@@ -72,6 +72,7 @@ void test_bpf_verif_scale(void)
{ "loop1.o", BPF_PROG_TYPE_RAW_TRACEPOINT },
{ "loop2.o", BPF_PROG_TYPE_RAW_TRACEPOINT },
{ "loop4.o", BPF_PROG_TYPE_SCHED_CLS },
+ { "loop5.o", BPF_PROG_TYPE_SCHED_CLS },
/* partial unroll. 19k insn in a loop.
* Total program size 20.8k insn.
diff --git a/tools/testing/selftests/bpf/progs/loop5.c b/tools/testing/selftests/bpf/progs/loop5.c
new file mode 100644
index 000000000000..28d1d668f07c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/loop5.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+char _license[] SEC("license") = "GPL";
+
+SEC("socket")
+int while_true(volatile struct __sk_buff* skb)
+{
+ int i = 0;
+
+ while (1) {
+ if (skb->len)
+ i += 3;
+ else
+ i += 7;
+ if (i == 9)
+ break;
+ barrier();
+ if (i == 10)
+ break;
+ barrier();
+ if (i == 13)
+ break;
+ barrier();
+ if (i == 14)
+ break;
+ }
+ return i;
+}