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/comedi/proc.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 drivers/comedi/proc.c (limited to 'drivers/comedi/proc.c') diff --git a/drivers/comedi/proc.c b/drivers/comedi/proc.c new file mode 100644 index 000000000..2e4496633 --- /dev/null +++ b/drivers/comedi/proc.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * /proc interface for comedi + * + * COMEDI - Linux Control and Measurement Device Interface + * Copyright (C) 1998 David A. Schleef + */ + +/* + * This is some serious bloatware. + * + * Taken from Dave A.'s PCL-711 driver, 'cuz I thought it + * was cool. + */ + +#include +#include "comedi_internal.h" +#include +#include + +static int comedi_read(struct seq_file *m, void *v) +{ + int i; + int devices_q = 0; + struct comedi_driver *driv; + + seq_printf(m, "comedi version " COMEDI_RELEASE "\nformat string: %s\n", + "\"%2d: %-20s %-20s %4d\", i, driver_name, board_name, n_subdevices"); + + for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) { + struct comedi_device *dev = comedi_dev_get_from_minor(i); + + if (!dev) + continue; + + down_read(&dev->attach_lock); + if (dev->attached) { + devices_q = 1; + seq_printf(m, "%2d: %-20s %-20s %4d\n", + i, dev->driver->driver_name, + dev->board_name, dev->n_subdevices); + } + up_read(&dev->attach_lock); + comedi_dev_put(dev); + } + if (!devices_q) + seq_puts(m, "no devices\n"); + + mutex_lock(&comedi_drivers_list_lock); + for (driv = comedi_drivers; driv; driv = driv->next) { + seq_printf(m, "%s:\n", driv->driver_name); + for (i = 0; i < driv->num_names; i++) + seq_printf(m, " %s\n", + *(char **)((char *)driv->board_name + + i * driv->offset)); + + if (!driv->num_names) + seq_printf(m, " %s\n", driv->driver_name); + } + mutex_unlock(&comedi_drivers_list_lock); + + return 0; +} + +void __init comedi_proc_init(void) +{ + if (!proc_create_single("comedi", 0444, NULL, comedi_read)) + pr_warn("comedi: unable to create proc entry\n"); +} + +void comedi_proc_cleanup(void) +{ + remove_proc_entry("comedi", NULL); +} -- cgit v1.3.1