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/pps/sysfs.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 drivers/pps/sysfs.c (limited to 'drivers/pps/sysfs.c') diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c new file mode 100644 index 000000000..134bc33f6 --- /dev/null +++ b/drivers/pps/sysfs.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * PPS sysfs support + * + * Copyright (C) 2007-2009 Rodolfo Giometti + */ + + +#include +#include +#include +#include + +/* + * Attribute functions + */ + +static ssize_t assert_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + if (!(pps->info.mode & PPS_CAPTUREASSERT)) + return 0; + + return sprintf(buf, "%lld.%09d#%d\n", + (long long) pps->assert_tu.sec, pps->assert_tu.nsec, + pps->assert_sequence); +} +static DEVICE_ATTR_RO(assert); + +static ssize_t clear_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + if (!(pps->info.mode & PPS_CAPTURECLEAR)) + return 0; + + return sprintf(buf, "%lld.%09d#%d\n", + (long long) pps->clear_tu.sec, pps->clear_tu.nsec, + pps->clear_sequence); +} +static DEVICE_ATTR_RO(clear); + +static ssize_t mode_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%4x\n", pps->info.mode); +} +static DEVICE_ATTR_RO(mode); + +static ssize_t echo_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%d\n", !!pps->info.echo); +} +static DEVICE_ATTR_RO(echo); + +static ssize_t name_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%s\n", pps->info.name); +} +static DEVICE_ATTR_RO(name); + +static ssize_t path_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%s\n", pps->info.path); +} +static DEVICE_ATTR_RO(path); + +static struct attribute *pps_attrs[] = { + &dev_attr_assert.attr, + &dev_attr_clear.attr, + &dev_attr_mode.attr, + &dev_attr_echo.attr, + &dev_attr_name.attr, + &dev_attr_path.attr, + NULL, +}; + +static const struct attribute_group pps_group = { + .attrs = pps_attrs, +}; + +const struct attribute_group *pps_groups[] = { + &pps_group, + NULL, +}; -- cgit v1.3.1