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, 137 insertions, 0 deletions

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
new file mode 100644
index 000000000..11835eb59
--- /dev/null
+++ b/arch/m68k/Kconfig
@@ -0,0 +1,137 @@
+# SPDX-License-Identifier: GPL-2.0
+config M68K
+	bool
+	default y
+	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_BINFMT_FLAT
+	select ARCH_HAS_CPU_CACHE_ALIASING
+	select ARCH_HAS_CPU_FINALIZE_INIT if MMU
+	select ARCH_HAS_CURRENT_STACK_POINTER
+	select ARCH_HAS_DMA_PREP_COHERENT if M68K_NONCOHERENT_DMA && !COLDFIRE
+	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if M68K_NONCOHERENT_DMA
+	select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
+	select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
+	select ARCH_NO_PREEMPT if !COLDFIRE
+	select ARCH_USE_MEMTEST if MMU_MOTOROLA
+	select ARCH_WANT_IPC_PARSE_VERSION
+	select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
+	select DMA_DIRECT_REMAP if M68K_NONCOHERENT_DMA && !COLDFIRE
+	select GENERIC_ATOMIC64
+	select GENERIC_CPU_DEVICES
+	select GENERIC_IOMAP if HAS_IOPORT && MMU && !COLDFIRE
+	select GENERIC_IRQ_SHOW
+	select GENERIC_LIB_ASHLDI3
+	select GENERIC_LIB_ASHRDI3
+	select GENERIC_LIB_LSHRDI3
+	select GENERIC_LIB_MULDI3
+	select GENERIC_PCI_IOMAP if PCI
+	select HAS_IOPORT if PCI || ISA || ATARI_ROM_ISA
+	select HAVE_ARCH_LIBGCC_H
+	select HAVE_ARCH_SECCOMP
+	select HAVE_ARCH_SECCOMP_FILTER
+	select HAVE_ASM_MODVERSIONS
+	select HAVE_DEBUG_BUGVERBOSE
+	select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_HAS_NO_UNALIGNED
+	select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
+	select HAVE_MOD_ARCH_SPECIFIC
+	select HAVE_UID16
+	select MMU_GATHER_NO_RANGE if MMU
+	select MODULES_USE_ELF_REL
+	select MODULES_USE_ELF_RELA
+	select NO_DMA if !MMU && !COLDFIRE
+	select OLD_SIGACTION
+	select OLD_SIGSUSPEND3
+	select UACCESS_MEMCPY if !MMU
+	select ZONE_DMA
+
+config CPU_BIG_ENDIAN
+	def_bool y
+
+config ARCH_HAS_ILOG2_U32
+	bool
+
+config ARCH_HAS_ILOG2_U64
+	bool
+
+config GENERIC_HWEIGHT
+	bool
+	default y
+
+config GENERIC_CALIBRATE_DELAY
+	bool
+	default y
+
+config GENERIC_CSUM
+	bool
+
+config TIME_LOW_RES
+	bool
+	default y
+
+config NO_IOPORT_MAP
+	def_bool y
+
+config HZ
+	int
+	default 1000 if CLEOPATRA
+	default 100
+
+config PGTABLE_LEVELS
+	default 2 if SUN3 || COLDFIRE
+	default 3
+
+config MMU
+	bool "MMU-based Paged Memory Management Support"
+	default y
+	help
+	  Select if you want MMU-based virtualised addressing space
+	  support by paged memory management. If unsure, say 'Y'.
+
+config MMU_MOTOROLA
+	def_bool MMU && M68KCLASSIC
+	select HAVE_PAGE_SIZE_4KB
+
+config MMU_COLDFIRE
+	def_bool MMU && COLDFIRE
+	select HAVE_PAGE_SIZE_8KB
+
+config MMU_SUN3
+	def_bool MMU && SUN3
+	select HAVE_PAGE_SIZE_8KB
+
+config ARCH_SUPPORTS_KEXEC
+	def_bool (M68KCLASSIC || SUN3) && MMU
+
+config BOOTINFO_PROC
+	bool "Export bootinfo in procfs"
+	depends on KEXEC && (M68KCLASSIC || SUN3)
+	help
+	  Say Y to export the bootinfo used to boot the kernel in a
+	  "bootinfo" file in procfs.  This is useful with kexec.
+
+menu "Platform setup"
+
+source "arch/m68k/Kconfig.cpu"
+
+source "arch/m68k/Kconfig.machine"
+
+source "arch/m68k/Kconfig.bus"
+
+endmenu
+
+menu "Kernel Features"
+
+endmenu
+
+if !MMU
+menu "Power management options"
+
+config PM
+	bool "Power Management support"
+	help
+	  Support processor power management modes
+
+endmenu
+endif
+
+source "arch/m68k/Kconfig.devices"