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, 168 insertions, 0 deletions

diff --git a/drivers/clk/qcom/turingcc-qcs404.c b/drivers/clk/qcom/turingcc-qcs404.c
new file mode 100644
index 000000000..2cd288d6c
--- /dev/null
+++ b/drivers/clk/qcom/turingcc-qcs404.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019, Linaro Ltd.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/pm_clock.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/clock/qcom,turingcc-qcs404.h>
+
+#include "clk-regmap.h"
+#include "clk-branch.h"
+#include "common.h"
+#include "reset.h"
+
+static struct clk_branch turing_wrapper_aon_cbcr = {
+	.halt_reg = 0x5098,
+	.halt_check = BRANCH_HALT,
+	.clkr = {
+		.enable_reg = 0x5098,
+		.enable_mask = BIT(0),
+		.hw.init = &(struct clk_init_data) {
+			.name = "turing_wrapper_aon_clk",
+			.ops = &clk_branch2_aon_ops,
+		},
+	},
+};
+
+static struct clk_branch turing_q6ss_ahbm_aon_cbcr = {
+	.halt_reg = 0x9000,
+	.halt_check = BRANCH_HALT,
+	.clkr = {
+		.enable_reg = 0x9000,
+		.enable_mask = BIT(0),
+		.hw.init = &(struct clk_init_data) {
+			.name = "turing_q6ss_ahbm_aon_cbcr",
+			.ops = &clk_branch2_ops,
+		},
+	},
+};
+
+static struct clk_branch turing_q6ss_q6_axim_clk = {
+	.halt_reg = 0xb000,
+	.halt_check = BRANCH_HALT,
+	.clkr = {
+		.enable_reg = 0xb000,
+		.enable_mask = BIT(0),
+		.hw.init = &(struct clk_init_data) {
+			.name = "turing_q6ss_q6_axim_clk",
+			.ops = &clk_branch2_aon_ops,
+		},
+	},
+};
+
+static struct clk_branch turing_q6ss_ahbs_aon_cbcr = {
+	.halt_reg = 0x10000,
+	.halt_check = BRANCH_HALT,
+	.clkr = {
+		.enable_reg = 0x10000,
+		.enable_mask = BIT(0),
+		.hw.init = &(struct clk_init_data) {
+			.name = "turing_q6ss_ahbs_aon_clk",
+			.ops = &clk_branch2_aon_ops,
+		},
+	},
+};
+
+static struct clk_branch turing_wrapper_qos_ahbs_aon_cbcr = {
+	.halt_reg = 0x11014,
+	.halt_check = BRANCH_HALT,
+	.clkr = {
+		.enable_reg = 0x11014,
+		.enable_mask = BIT(0),
+		.hw.init = &(struct clk_init_data) {
+			.name = "turing_wrapper_qos_ahbs_aon_clk",
+			.ops = &clk_branch2_aon_ops,
+		},
+	},
+};
+
+static struct clk_regmap *turingcc_clocks[] = {
+	[TURING_WRAPPER_AON_CLK] = &turing_wrapper_aon_cbcr.clkr,
+	[TURING_Q6SS_AHBM_AON_CLK] = &turing_q6ss_ahbm_aon_cbcr.clkr,
+	[TURING_Q6SS_Q6_AXIM_CLK] = &turing_q6ss_q6_axim_clk.clkr,
+	[TURING_Q6SS_AHBS_AON_CLK] = &turing_q6ss_ahbs_aon_cbcr.clkr,
+	[TURING_WRAPPER_QOS_AHBS_AON_CLK] = &turing_wrapper_qos_ahbs_aon_cbcr.clkr,
+};
+
+static const struct regmap_config turingcc_regmap_config = {
+	.reg_bits	= 32,
+	.reg_stride	= 4,
+	.val_bits	= 32,
+	.max_register	= 0x23004,
+	.fast_io	= true,
+};
+
+static const struct qcom_cc_desc turingcc_desc = {
+	.config = &turingcc_regmap_config,
+	.clks = turingcc_clocks,
+	.num_clks = ARRAY_SIZE(turingcc_clocks),
+};
+
+static int turingcc_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = devm_pm_runtime_enable(&pdev->dev);
+	if (ret)
+		return ret;
+
+	ret = devm_pm_clk_create(&pdev->dev);
+	if (ret)
+		return ret;
+
+	ret = pm_clk_add(&pdev->dev, NULL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to acquire iface clock\n");
+		return ret;
+	}
+
+	ret = pm_runtime_resume_and_get(&pdev->dev);
+	if (ret)
+		return ret;
+
+	ret = qcom_cc_probe(pdev, &turingcc_desc);
+	if (ret < 0)
+		goto err_put_rpm;
+
+	pm_runtime_put(&pdev->dev);
+
+	return 0;
+
+err_put_rpm:
+	pm_runtime_put_sync(&pdev->dev);
+
+	return ret;
+}
+
+static const struct dev_pm_ops turingcc_pm_ops = {
+	SET_RUNTIME_PM_OPS(pm_clk_suspend, pm_clk_resume, NULL)
+};
+
+static const struct of_device_id turingcc_match_table[] = {
+	{ .compatible = "qcom,qcs404-turingcc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, turingcc_match_table);
+
+static struct platform_driver turingcc_driver = {
+	.probe		= turingcc_probe,
+	.driver		= {
+		.name	= "qcs404-turingcc",
+		.of_match_table = turingcc_match_table,
+		.pm = &turingcc_pm_ops,
+	},
+};
+
+module_platform_driver(turingcc_driver);
+
+MODULE_DESCRIPTION("Qualcomm QCS404 Turing Clock Controller");
+MODULE_LICENSE("GPL v2");