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, 104 insertions, 0 deletions

diff --git a/fs/xfs/xfs_super.h b/fs/xfs/xfs_super.h
new file mode 100644
index 000000000..c0e85c1e4
--- /dev/null
+++ b/fs/xfs/xfs_super.h
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#ifndef __XFS_SUPER_H__
+#define __XFS_SUPER_H__
+
+#include <linux/exportfs.h>
+
+#ifdef CONFIG_XFS_QUOTA
+extern int xfs_qm_init(void);
+extern void xfs_qm_exit(void);
+# define XFS_QUOTA_STRING	"quota, "
+#else
+# define xfs_qm_init()	(0)
+# define xfs_qm_exit()	do { } while (0)
+# define XFS_QUOTA_STRING
+#endif
+
+#ifdef CONFIG_XFS_POSIX_ACL
+# define XFS_ACL_STRING		"ACLs, "
+# define set_posix_acl_flag(sb)	((sb)->s_flags |= SB_POSIXACL)
+#else
+# define XFS_ACL_STRING
+# define set_posix_acl_flag(sb)	do { } while (0)
+#endif
+
+#define XFS_SECURITY_STRING	"security attributes, "
+
+#ifdef CONFIG_XFS_RT
+# define XFS_REALTIME_STRING	"realtime, "
+#else
+# define XFS_REALTIME_STRING
+#endif
+
+#ifdef CONFIG_XFS_ONLINE_SCRUB
+# define XFS_SCRUB_STRING	"scrub, "
+#else
+# define XFS_SCRUB_STRING
+#endif
+
+#ifdef CONFIG_XFS_ONLINE_REPAIR
+# define XFS_REPAIR_STRING	"repair, "
+#else
+# define XFS_REPAIR_STRING
+#endif
+
+#ifdef CONFIG_XFS_WARN
+# define XFS_WARN_STRING	"verbose warnings, "
+#else
+# define XFS_WARN_STRING
+#endif
+
+#ifdef CONFIG_XFS_ASSERT_FATAL
+# define XFS_ASSERT_FATAL_STRING	"fatal assert, "
+#else
+# define XFS_ASSERT_FATAL_STRING
+#endif
+
+#ifdef DEBUG
+# define XFS_DBG_STRING		"debug"
+#else
+# define XFS_DBG_STRING		"no debug"
+#endif
+
+#define XFS_VERSION_STRING	"SGI XFS"
+#define XFS_BUILD_OPTIONS	XFS_ACL_STRING \
+				XFS_SECURITY_STRING \
+				XFS_REALTIME_STRING \
+				XFS_SCRUB_STRING \
+				XFS_REPAIR_STRING \
+				XFS_WARN_STRING \
+				XFS_QUOTA_STRING \
+				XFS_ASSERT_FATAL_STRING \
+				XFS_DBG_STRING /* DBG must be last */
+
+#ifdef DEBUG
+# define XFS_WQFLAGS(wqflags)	(WQ_SYSFS | (wqflags))
+#else
+# define XFS_WQFLAGS(wqflags)	(wqflags)
+#endif
+
+struct xfs_inode;
+struct xfs_mount;
+struct xfs_buftarg;
+struct block_device;
+
+extern void xfs_flush_inodes(struct xfs_mount *mp);
+extern xfs_agnumber_t xfs_set_inode_alloc(struct xfs_mount *,
+					   xfs_agnumber_t agcount);
+
+extern const struct export_operations xfs_export_operations;
+extern const struct quotactl_ops xfs_quotactl_operations;
+
+extern void xfs_reinit_percpu_counters(struct xfs_mount *mp);
+
+extern struct workqueue_struct *xfs_discard_wq;
+
+#define XFS_M(sb)		((struct xfs_mount *)((sb)->s_fs_info))
+
+struct dentry *xfs_debugfs_mkdir(const char *name, struct dentry *parent);
+
+#endif	/* __XFS_SUPER_H__ */