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, 45 insertions, 0 deletions

diff --git a/arch/m68k/Kconfig.debug b/arch/m68k/Kconfig.debug
new file mode 100644
index 000000000..d036f9038
--- /dev/null
+++ b/arch/m68k/Kconfig.debug
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config BOOTPARAM
+	bool "Compiled-in Kernel Boot Parameter"
+
+config BOOTPARAM_STRING
+	string "Kernel Boot Parameter"
+	default "console=ttyS0,19200"
+	depends on BOOTPARAM
+
+config EARLY_PRINTK
+	bool "Early printk"
+	depends on MMU_MOTOROLA
+	help
+	  Write kernel log output directly to a serial port.
+	  Where implemented, output goes to the framebuffer as well.
+	  PROM console functionality on Sun 3x is not affected by this option.
+
+	  Pass "earlyprintk" on the kernel command line to get a
+	  boot console.
+
+	  This is useful for kernel debugging when your machine crashes very
+	  early, i.e. before the normal console driver is loaded.
+	  You should normally say N here, unless you want to debug such a crash.
+
+if !MMU
+
+config FULLDEBUG
+	bool "Full Symbolic/Source Debugging support"
+	help
+	  Enable debugging symbols on kernel build.
+
+config HIGHPROFILE
+	bool "Use fast second timer for profiling"
+	depends on COLDFIRE
+	help
+	  Use a fast secondary clock to produce profiling information.
+
+config BDM_DISABLE
+	bool "Disable BDM signals"
+	depends on COLDFIRE
+	help
+	  Disable the ColdFire CPU's BDM signals.
+
+endif