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, 116 insertions, 0 deletions

diff --git a/sound/soc/codecs/bt-sco.c b/sound/soc/codecs/bt-sco.c
new file mode 100644
index 000000000..b085885e3
--- /dev/null
+++ b/sound/soc/codecs/bt-sco.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for generic Bluetooth SCO link
+ * Copyright 2011 Lars-Peter Clausen <lars@metafoo.de>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <sound/soc.h>
+
+static const struct snd_soc_dapm_widget bt_sco_widgets[] = {
+	SND_SOC_DAPM_INPUT("RX"),
+	SND_SOC_DAPM_OUTPUT("TX"),
+	SND_SOC_DAPM_AIF_IN("BT_SCO_RX", "Playback", 0,
+			    SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_OUT("BT_SCO_TX", "Capture", 0,
+			     SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_IN("BT_SCO_RX_WB", "WB Playback", 0,
+			    SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_OUT("BT_SCO_TX_WB", "WB Capture", 0,
+			     SND_SOC_NOPM, 0, 0),
+};
+
+static const struct snd_soc_dapm_route bt_sco_routes[] = {
+	{ "BT_SCO_TX", NULL, "RX" },
+	{ "TX", NULL, "BT_SCO_RX" },
+	{ "BT_SCO_TX_WB", NULL, "RX" },
+	{ "TX", NULL, "BT_SCO_RX_WB" },
+};
+
+static struct snd_soc_dai_driver bt_sco_dai[] = {
+	{
+		.name = "bt-sco-pcm",
+		.playback = {
+			.stream_name = "Playback",
+			.channels_min = 1,
+			.channels_max = 1,
+			.rates = SNDRV_PCM_RATE_8000,
+			.formats = SNDRV_PCM_FMTBIT_S16_LE,
+		},
+		.capture = {
+			 .stream_name = "Capture",
+			.channels_min = 1,
+			.channels_max = 1,
+			.rates = SNDRV_PCM_RATE_8000,
+			.formats = SNDRV_PCM_FMTBIT_S16_LE,
+		},
+	},
+	{
+		.name = "bt-sco-pcm-wb",
+		.playback = {
+			.stream_name = "WB Playback",
+			.channels_min = 1,
+			.channels_max = 1,
+			.rates = SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000,
+			.formats = SNDRV_PCM_FMTBIT_S16_LE,
+		},
+		.capture = {
+			 .stream_name = "WB Capture",
+			.channels_min = 1,
+			.channels_max = 1,
+			.rates = SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000,
+			.formats = SNDRV_PCM_FMTBIT_S16_LE,
+		},
+	}
+};
+
+static const struct snd_soc_component_driver soc_component_dev_bt_sco = {
+	.dapm_widgets		= bt_sco_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(bt_sco_widgets),
+	.dapm_routes		= bt_sco_routes,
+	.num_dapm_routes	= ARRAY_SIZE(bt_sco_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static int bt_sco_probe(struct platform_device *pdev)
+{
+	return devm_snd_soc_register_component(&pdev->dev,
+				      &soc_component_dev_bt_sco,
+				      bt_sco_dai, ARRAY_SIZE(bt_sco_dai));
+}
+
+static const struct platform_device_id bt_sco_driver_ids[] = {
+	{ .name = "dfbmcs320" },
+	{ .name = "bt-sco" },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, bt_sco_driver_ids);
+
+#if defined(CONFIG_OF)
+static const struct of_device_id bt_sco_codec_of_match[] = {
+	{ .compatible = "delta,dfbmcs320", },
+	{ .compatible = "linux,bt-sco", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bt_sco_codec_of_match);
+#endif
+
+static struct platform_driver bt_sco_driver = {
+	.driver = {
+		.name = "bt-sco",
+		.of_match_table = of_match_ptr(bt_sco_codec_of_match),
+	},
+	.probe = bt_sco_probe,
+	.id_table = bt_sco_driver_ids,
+};
+
+module_platform_driver(bt_sco_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("ASoC generic bluetooth sco link driver");
+MODULE_LICENSE("GPL");