Merge branch 'bpf-bounded-loops'

Alexei Starovoitov says:

====================
v2->v3: fixed issues in backtracking pointed out by Andrii.
The next step is to add a lot more tests for backtracking.

v1->v2: addressed Andrii's feedback.

this patch set introduces verifier support for bounded loops and
adds several other improvements.
Ideally they would be introduced one at a time,
but to support bounded loop the verifier needs to 'step back'
in the patch 1. That patch introduces tracking of spill/fill
of constants through the stack. Though it's a useful feature
it hurts cilium tests.
Patch 3 introduces another feature by extending is_branch_taken
logic to 'if rX op rY' conditions. This feature is also
necessary to support bounded loops.
Then patch 4 adds support for the loops while adding
key heuristics with jmp_processed.
Introduction of parentage chain of verifier states in patch 4
allows patch 9 to add backtracking of precise scalar registers
which finally resolves degradation from patch 1.

The end result is much faster verifier for existing programs
and new support for loops.
See patch 8 for many kinds of loops that are now validated.
Patch 9 is the most tricky one and could be rewritten with
a different algorithm in the future.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/tools/testing/selftests/bpf/progs/pyperf.h b/tools/testing/selftests/bpf/progs/pyperf.h
index 0cc5e4ee90bd..6b0781391be5 100644
--- a/tools/testing/selftests/bpf/progs/pyperf.h
+++ b/tools/testing/selftests/bpf/progs/pyperf.h
@@ -220,7 +220,11 @@ static inline __attribute__((__always_inline__)) int __on_event(struct pt_regs *
 		int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
 		if (symbol_counter == NULL)
 			return 0;
-#pragma unroll
+#ifdef NO_UNROLL
+#pragma clang loop unroll(disable)
+#else
+#pragma clang loop unroll(full)
+#endif
 		/* Unwind python stack */
 		for (int i = 0; i < STACK_MAX_LEN; ++i) {
 			if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {