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, 61 insertions, 0 deletions

diff --git a/Documentation/filesystems/hfsplus.rst b/Documentation/filesystems/hfsplus.rst
new file mode 100644
index 000000000..f02f4f5fc
--- /dev/null
+++ b/Documentation/filesystems/hfsplus.rst
@@ -0,0 +1,61 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================
+Macintosh HFSPlus Filesystem for Linux
+======================================
+
+HFSPlus is a filesystem first introduced in MacOS 8.1.
+HFSPlus has several extensions to HFS, including 32-bit allocation
+blocks, 255-character unicode filenames, and file sizes of 2^63 bytes.
+
+
+Mount options
+=============
+
+When mounting an HFSPlus filesystem, the following options are accepted:
+
+  creator=cccc, type=cccc
+	Specifies the creator/type values as shown by the MacOS finder
+	used for creating new files.  Default values: '????'.
+
+  uid=n, gid=n
+	Specifies the user/group that owns all files on the filesystem
+	that have uninitialized permissions structures.
+	Default:  user/group id of the mounting process.
+
+  umask=n
+	Specifies the umask (in octal) used for files and directories
+	that have uninitialized permissions structures.
+	Default:  umask of the mounting process.
+
+  session=n
+	Select the CDROM session to mount as HFSPlus filesystem.  Defaults to
+	leaving that decision to the CDROM driver.  This option will fail
+	with anything but a CDROM as underlying devices.
+
+  part=n
+	Select partition number n from the devices.  This option only makes
+	sense for CDROMs because they can't be partitioned under Linux.
+	For disk devices the generic partition parsing code does this
+	for us.  Defaults to not parsing the partition table at all.
+
+  decompose
+	Decompose file name characters.
+
+  nodecompose
+	Do not decompose file name characters.
+
+  force
+	Used to force write access to volumes that are marked as journalled
+	or locked.  Use at your own risk.
+
+  nls=cccc
+	Encoding to use when presenting file names.
+
+
+References
+==========
+
+kernel source:		<file:fs/hfsplus>
+
+Apple Technote 1150	https://developer.apple.com/legacy/library/technotes/tn/tn1150.html