selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/clk/mediatek/clk-mt6765-vcodec.c b/drivers/clk/mediatek/clk-mt6765-vcodec.c
new file mode 100644
index 000000000..f309d1090
--- /dev/null
+++ b/drivers/clk/mediatek/clk-mt6765-vcodec.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ * Author: Owen Chen <owen.chen@mediatek.com>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/platform_device.h>
+
+#include "clk-mtk.h"
+#include "clk-gate.h"
+
+#include <dt-bindings/clock/mt6765-clk.h>
+
+static const struct mtk_gate_regs venc_cg_regs = {
+	.set_ofs = 0x4,
+	.clr_ofs = 0x8,
+	.sta_ofs = 0x0,
+};
+
+#define GATE_VENC(_id, _name, _parent, _shift)				\
+	GATE_MTK(_id, _name, _parent, &venc_cg_regs, _shift, &mtk_clk_gate_ops_setclr_inv)
+
+static const struct mtk_gate venc_clks[] = {
+	GATE_VENC(CLK_VENC_SET0_LARB, "venc_set0_larb", "mm_ck", 0),
+	GATE_VENC(CLK_VENC_SET1_VENC, "venc_set1_venc", "mm_ck", 4),
+	GATE_VENC(CLK_VENC_SET2_JPGENC, "jpgenc", "mm_ck", 8),
+	GATE_VENC(CLK_VENC_SET3_VDEC, "venc_set3_vdec", "mm_ck", 12),
+};
+
+static const struct mtk_clk_desc venc_desc = {
+	.clks = venc_clks,
+	.num_clks = ARRAY_SIZE(venc_clks),
+};
+
+static const struct of_device_id of_match_clk_mt6765_vcodec[] = {
+	{
+		.compatible = "mediatek,mt6765-vcodecsys",
+		.data = &venc_desc,
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, of_match_clk_mt6765_vcodec);
+
+static struct platform_driver clk_mt6765_vcodec_drv = {
+	.probe = mtk_clk_simple_probe,
+	.remove = mtk_clk_simple_remove,
+	.driver = {
+		.name = "clk-mt6765-vcodec",
+		.of_match_table = of_match_clk_mt6765_vcodec,
+	},
+};
+module_platform_driver(clk_mt6765_vcodec_drv);
+
+MODULE_DESCRIPTION("MediaTek MT6765 Video Codec clocks driver");
+MODULE_LICENSE("GPL");