selftests/bpf: Test packet range of pointers sharing an idgrafted

Add tests where two packet pointers share an id and tightening one
pointer's umax from its var_off would put it less than their constant
distance from the other's umax: with an index & 0x38 capped at 50, the
base pointer keeps umax 50, so the pointer 8 bytes further on must keep
umax 58, even though its known bits allow at most 56.

These refused a valid program or accepted an out-of-bounds access before
the fix:

- check the advanced copy, load through the base: valid, was refused;
- check the base, load the byte at base + 1 through a copy advanced by
  8: was accepted;
- check base + 4, load 4 bytes at base + 2 through base + 8: reads two
  bytes past the checked range, was accepted;
- the same as the second with data_meta pointers checked against data:
  was accepted.

These pass with and without the fix and cover nearby paths:

- subtract an unknown scalar from a checked pointer and load below it
  (the range is kept across a new id);
- reach a load through two paths whose checks cover 8 and 7 bytes after
  the loaded pointer; the second path must not be pruned by the first;
- spill a copy of a pointer, check the pointer, fill the copy and load
  one byte past the checked range: the load is refused, and the copy
  has the range of the check.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/include/drm/intel/step.h b/include/drm/intel/step.h
new file mode 100644
index 000000000..4de752010
--- /dev/null
+++ b/include/drm/intel/step.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2026 Intel Corporation */
+
+#ifndef __STEP_H__
+#define __STEP_H__
+
+#define STEP_ENUM_VAL(name)  STEP_##name,
+
+#define STEP_NAME_LIST(func)		\
+	func(A0)			\
+	func(A1)			\
+	func(A2)			\
+	func(A3)			\
+	func(B0)			\
+	func(B1)			\
+	func(B2)			\
+	func(B3)			\
+	func(C0)			\
+	func(C1)			\
+	func(C2)			\
+	func(C3)			\
+	func(D0)			\
+	func(D1)			\
+	func(D2)			\
+	func(D3)			\
+	func(E0)			\
+	func(E1)			\
+	func(E2)			\
+	func(E3)			\
+	func(F0)			\
+	func(F1)			\
+	func(F2)			\
+	func(F3)			\
+	func(G0)			\
+	func(G1)			\
+	func(G2)			\
+	func(G3)			\
+	func(H0)			\
+	func(H1)			\
+	func(H2)			\
+	func(H3)			\
+	func(I0)			\
+	func(I1)			\
+	func(I2)			\
+	func(I3)			\
+	func(J0)			\
+	func(J1)			\
+	func(J2)			\
+	func(J3)
+
+/*
+ * Symbolic steppings that do not match the hardware. These are valid both as gt
+ * and display steppings as symbolic names.
+ */
+enum intel_step {
+	STEP_NONE = 0,
+	STEP_NAME_LIST(STEP_ENUM_VAL)
+	STEP_FUTURE,
+	STEP_FOREVER,
+};
+
+#endif /* __STEP_H__ */