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/cs42l43-i2c.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 drivers/mfd/cs42l43-i2c.c (limited to 'drivers/mfd/cs42l43-i2c.c') diff --git a/drivers/mfd/cs42l43-i2c.c b/drivers/mfd/cs42l43-i2c.c new file mode 100644 index 000000000..44ad63129 --- /dev/null +++ b/drivers/mfd/cs42l43-i2c.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * CS42L43 I2C driver + * + * Copyright (C) 2022-2023 Cirrus Logic, Inc. and + * Cirrus Logic International Semiconductor Ltd. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "cs42l43.h" + +static const struct regmap_config cs42l43_i2c_regmap = { + .reg_bits = 32, + .reg_stride = 4, + .val_bits = 32, + .reg_format_endian = REGMAP_ENDIAN_BIG, + .val_format_endian = REGMAP_ENDIAN_BIG, + + .max_register = CS42L43_MCU_RAM_MAX, + .readable_reg = cs42l43_readable_register, + .volatile_reg = cs42l43_volatile_register, + .precious_reg = cs42l43_precious_register, + + .cache_type = REGCACHE_MAPLE, + .reg_defaults = cs42l43_reg_default, + .num_reg_defaults = ARRAY_SIZE(cs42l43_reg_default), +}; + +static int cs42l43_i2c_probe(struct i2c_client *i2c) +{ + struct cs42l43 *cs42l43; + + cs42l43 = devm_kzalloc(&i2c->dev, sizeof(*cs42l43), GFP_KERNEL); + if (!cs42l43) + return -ENOMEM; + + cs42l43->dev = &i2c->dev; + cs42l43->irq = i2c->irq; + /* A device on an I2C is always attached by definition. */ + cs42l43->attached = true; + cs42l43->variant_id = (long)device_get_match_data(cs42l43->dev); + + cs42l43->regmap = devm_regmap_init_i2c(i2c, &cs42l43_i2c_regmap); + if (IS_ERR(cs42l43->regmap)) + return dev_err_probe(cs42l43->dev, PTR_ERR(cs42l43->regmap), + "Failed to allocate regmap\n"); + + return cs42l43_dev_probe(cs42l43); +} + +#if IS_ENABLED(CONFIG_OF) +static const struct of_device_id cs42l43_of_match[] = { + { .compatible = "cirrus,cs42l43", .data = (void *)CS42L43_DEVID_VAL }, + { .compatible = "cirrus,cs42l43b", .data = (void *)CS42L43B_DEVID_VAL }, + {} +}; +MODULE_DEVICE_TABLE(of, cs42l43_of_match); +#endif + +#if IS_ENABLED(CONFIG_ACPI) +static const struct acpi_device_id cs42l43_acpi_match[] = { + { "CSC4243", CS42L43_DEVID_VAL }, + { "CSC2A3B", CS42L43B_DEVID_VAL }, + {} +}; +MODULE_DEVICE_TABLE(acpi, cs42l43_acpi_match); +#endif + +static struct i2c_driver cs42l43_i2c_driver = { + .driver = { + .name = "cs42l43", + .pm = pm_ptr(&cs42l43_pm_ops), + .of_match_table = of_match_ptr(cs42l43_of_match), + .acpi_match_table = ACPI_PTR(cs42l43_acpi_match), + }, + + .probe = cs42l43_i2c_probe, +}; +module_i2c_driver(cs42l43_i2c_driver); + +MODULE_IMPORT_NS("MFD_CS42L43"); + +MODULE_DESCRIPTION("CS42L43 I2C Driver"); +MODULE_AUTHOR("Charles Keepax "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1