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, 50 insertions, 0 deletions

diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
new file mode 100644
index 000000000..d5bce83ad
--- /dev/null
+++ b/fs/ext2/Kconfig
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config EXT2_FS
+	tristate "Second extended fs support (DEPRECATED)"
+	select BUFFER_HEAD
+	select FS_IOMAP
+	help
+	  Ext2 is a standard Linux file system for hard disks.
+
+	  This filesystem driver is deprecated because it does not properly
+	  support inode time stamps beyond 03:14:07 UTC on 19 January 2038.
+
+	  Ext2 users are advised to use ext4 driver to access their filesystem.
+	  The driver is fully compatible, supports filesystems without journal
+          or extents, and also supports larger time stamps if the filesystem
+          is created with at least 256 byte inodes.
+
+	  This code is kept as a simple reference for filesystem developers.
+
+	  If unsure, say N.
+
+config EXT2_FS_XATTR
+	bool "Ext2 extended attributes"
+	depends on EXT2_FS
+	help
+	  Extended attributes are name:value pairs associated with inodes by
+	  the kernel or by users (see the attr(5) manual page for details).
+
+	  If unsure, say N.
+
+config EXT2_FS_POSIX_ACL
+	bool "Ext2 POSIX Access Control Lists"
+	depends on EXT2_FS_XATTR
+	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 EXT2_FS_SECURITY
+	bool "Ext2 Security Labels"
+	depends on EXT2_FS_XATTR
+	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 ext2 filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.