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, 51 insertions, 0 deletions

diff --git a/fs/jfs/Kconfig b/fs/jfs/Kconfig
new file mode 100644
index 000000000..3728cf4d9
--- /dev/null
+++ b/fs/jfs/Kconfig
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config JFS_FS
+	tristate "JFS filesystem support"
+	select BUFFER_HEAD
+	select NLS
+	select NLS_UCS2_UTILS
+	select CRC32
+	select LEGACY_DIRECT_IO
+	help
+	  This is a port of IBM's Journaled Filesystem .  More information is
+	  available in the file <file:Documentation/admin-guide/jfs.rst>.
+
+	  If you do not intend to use the JFS filesystem, say N.
+
+config JFS_POSIX_ACL
+	bool "JFS POSIX Access Control Lists"
+	depends on JFS_FS
+	select FS_POSIX_ACL
+	help
+	  Posix Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  If you don't know what Access Control Lists are, say N
+
+config JFS_SECURITY
+	bool "JFS Security Labels"
+	depends on JFS_FS
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux.  This option
+	  enables an extended attribute handler for file security
+	  labels in the jfs filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.
+
+config JFS_DEBUG
+	bool "JFS debugging"
+	depends on JFS_FS
+	help
+	  If you are experiencing any problems with the JFS filesystem, say
+	  Y here.  This will result in additional debugging messages to be
+	  written to the system log.  Under normal circumstances, this
+	  results in very little overhead.
+
+config JFS_STATISTICS
+	bool "JFS statistics"
+	depends on JFS_FS
+	help
+	  Enabling this option will cause statistics from the JFS file system
+	  to be made available to the user in the /proc/fs/jfs/ directory.