From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock 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 Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/mfd/cs40l50-spi.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 drivers/mfd/cs40l50-spi.c (limited to 'drivers/mfd/cs40l50-spi.c') diff --git a/drivers/mfd/cs40l50-spi.c b/drivers/mfd/cs40l50-spi.c new file mode 100644 index 000000000..53526b595 --- /dev/null +++ b/drivers/mfd/cs40l50-spi.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * CS40L50 Advanced Haptic Driver with waveform memory, + * integrated DSP, and closed-loop algorithms + * + * Copyright 2024 Cirrus Logic, Inc. + * + * Author: James Ogletree + */ + +#include +#include + +static int cs40l50_spi_probe(struct spi_device *spi) +{ + struct cs40l50 *cs40l50; + + cs40l50 = devm_kzalloc(&spi->dev, sizeof(*cs40l50), GFP_KERNEL); + if (!cs40l50) + return -ENOMEM; + + spi_set_drvdata(spi, cs40l50); + + cs40l50->dev = &spi->dev; + cs40l50->irq = spi->irq; + + cs40l50->regmap = devm_regmap_init_spi(spi, &cs40l50_regmap); + if (IS_ERR(cs40l50->regmap)) + return dev_err_probe(cs40l50->dev, PTR_ERR(cs40l50->regmap), + "Failed to initialize register map\n"); + + return cs40l50_probe(cs40l50); +} + +static void cs40l50_spi_remove(struct spi_device *spi) +{ + struct cs40l50 *cs40l50 = spi_get_drvdata(spi); + + cs40l50_remove(cs40l50); +} + +static const struct spi_device_id cs40l50_id_spi[] = { + { "cs40l50" }, + {} +}; +MODULE_DEVICE_TABLE(spi, cs40l50_id_spi); + +static const struct of_device_id cs40l50_of_match[] = { + { .compatible = "cirrus,cs40l50" }, + {} +}; +MODULE_DEVICE_TABLE(of, cs40l50_of_match); + +static struct spi_driver cs40l50_spi_driver = { + .driver = { + .name = "cs40l50", + .of_match_table = cs40l50_of_match, + .pm = pm_ptr(&cs40l50_pm_ops), + }, + .id_table = cs40l50_id_spi, + .probe = cs40l50_spi_probe, + .remove = cs40l50_spi_remove, +}; +module_spi_driver(cs40l50_spi_driver); + +MODULE_DESCRIPTION("CS40L50 SPI Driver"); +MODULE_AUTHOR("James Ogletree, Cirrus Logic Inc. "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1