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, 43 insertions, 0 deletions

diff --git a/drivers/hid/intel-thc-hid/Kconfig b/drivers/hid/intel-thc-hid/Kconfig
new file mode 100644
index 000000000..9d74e53b8
--- /dev/null
+++ b/drivers/hid/intel-thc-hid/Kconfig
@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2024, Intel Corporation.
+
+menu "Intel THC HID Support"
+	depends on X86_64 && PCI
+
+config INTEL_THC_HID
+	tristate "Intel Touch Host Controller"
+	depends on ACPI
+	select SGL_ALLOC
+	help
+	  THC (Touch Host Controller) is the name of the IP block in PCH that
+	  interfaces with Touch Devices (ex: touchscreen, touchpad etc.). It
+	  is comprised of 3 key functional blocks: A natively half-duplex
+	  Quad I/O capable SPI master; a low latency I2C interface to support
+	  HIDI2C compliant devices; a hardware sequencer with Read/Write DMA
+	  capability to system memory.
+
+	  Say Y/M here if you want to support Intel THC. If unsure, say N.
+
+config INTEL_QUICKSPI
+	tristate "Intel QuickSPI driver based on Intel Touch Host Controller"
+	depends on INTEL_THC_HID
+	help
+	  Intel QuickSPI, based on Touch Host Controller (THC), implements
+	  HIDSPI (HID over SPI) protocol. It configures THC to work at SPI
+	  mode, and controls THC hardware sequencer to accelerate HIDSPI
+	  transaction flow.
+
+	  Say Y/M here if you want to support Intel QuickSPI. If unsure, say N.
+
+config INTEL_QUICKI2C
+	tristate "Intel QuickI2C driver based on Intel Touch Host Controller"
+	depends on INTEL_THC_HID
+	help
+	  Intel QuickI2C, uses Touch Host Controller (THC) hardware, implements
+	  HIDI2C (HID over I2C) protocol. It configures THC to work in I2C
+	  mode, and controls THC hardware sequencer to accelerate HIDI2C
+	  transaction flow.
+
+	  Say Y/M here if you want to support Intel QuickI2C. If unsure, say N.
+
+endmenu