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, 31 insertions, 0 deletions

diff --git a/drivers/media/common/Kconfig b/drivers/media/common/Kconfig
new file mode 100644
index 000000000..adcb66553
--- /dev/null
+++ b/drivers/media/common/Kconfig
@@ -0,0 +1,31 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# Used by common drivers, when they need to ask questions
+config MEDIA_COMMON_OPTIONS
+	bool
+
+comment "common driver options"
+	depends on MEDIA_COMMON_OPTIONS
+
+config CYPRESS_FIRMWARE
+	tristate
+	depends on USB
+
+config TTPCI_EEPROM
+        tristate
+        depends on I2C
+
+config UVC_COMMON
+	tristate
+
+config VIDEO_CX2341X
+	tristate
+
+config VIDEO_TVEEPROM
+	tristate
+	depends on I2C
+
+source "drivers/media/common/b2c2/Kconfig"
+source "drivers/media/common/saa7146/Kconfig"
+source "drivers/media/common/siano/Kconfig"
+source "drivers/media/common/v4l2-tpg/Kconfig"
+source "drivers/media/common/videobuf2/Kconfig"