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, 16 insertions, 0 deletions

diff --git a/fs/ext2/Makefile b/fs/ext2/Makefile
new file mode 100644
index 000000000..8860948ef
--- /dev/null
+++ b/fs/ext2/Makefile
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux ext2-filesystem routines.
+#
+
+obj-$(CONFIG_EXT2_FS) += ext2.o
+
+ext2-y := balloc.o dir.o file.o ialloc.o inode.o \
+	  ioctl.o namei.o super.o symlink.o trace.o
+
+# For tracepoints to include our trace.h from tracepoint infrastructure
+CFLAGS_trace.o := -I$(src)
+
+ext2-$(CONFIG_EXT2_FS_XATTR)	 += xattr.o xattr_user.o xattr_trusted.o
+ext2-$(CONFIG_EXT2_FS_POSIX_ACL) += acl.o
+ext2-$(CONFIG_EXT2_FS_SECURITY)	 += xattr_security.o