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, 29 insertions, 0 deletions

diff --git a/fs/adfs/Kconfig b/fs/adfs/Kconfig
new file mode 100644
index 000000000..1b97058f0
--- /dev/null
+++ b/fs/adfs/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ADFS_FS
+	tristate "ADFS file system support"
+	depends on BLOCK
+	select BUFFER_HEAD
+	help
+	  The Acorn Disc Filing System is the standard file system of the
+	  RiscOS operating system which runs on Acorn's ARM-based Risc PC
+	  systems and the Acorn Archimedes range of machines. If you say Y
+	  here, Linux will be able to read from ADFS partitions on hard drives
+	  and from ADFS-formatted floppy discs. If you also want to be able to
+	  write to those devices, say Y to "ADFS write support" below.
+
+	  The ADFS partition should be the first partition (i.e.,
+	  /dev/[hs]d?1) on each of your drives. Please read the file
+	  <file:Documentation/filesystems/adfs.rst> for further details.
+
+	  To compile this code as a module, choose M here: the module will be
+	  called adfs.
+
+	  If unsure, say N.
+
+config ADFS_FS_RW
+	bool "ADFS write support (DANGEROUS)"
+	depends on ADFS_FS
+	help
+	  If you say Y here, you will be able to write to ADFS partitions on
+	  hard drives and ADFS-formatted floppy disks. This is experimental
+	  codes, so if you're unsure, say N.