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, 65 insertions, 0 deletions

diff --git a/fs/xfs/xfs_trace.c b/fs/xfs/xfs_trace.c
new file mode 100644
index 000000000..912713a8a
--- /dev/null
+++ b/fs/xfs/xfs_trace.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2009, Christoph Hellwig
+ * All Rights Reserved.
+ */
+#include "xfs_platform.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_bit.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_group.h"
+#include "xfs_defer.h"
+#include "xfs_da_format.h"
+#include "xfs_inode.h"
+#include "xfs_btree.h"
+#include "xfs_da_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_bmap.h"
+#include "xfs_attr.h"
+#include "xfs_trans.h"
+#include "xfs_log.h"
+#include "xfs_log_priv.h"
+#include "xfs_trans_priv.h"
+#include "xfs_buf_item.h"
+#include "xfs_quota.h"
+#include "xfs_dquot_item.h"
+#include "xfs_dquot.h"
+#include "xfs_log_recover.h"
+#include "xfs_filestream.h"
+#include "xfs_fsmap.h"
+#include "xfs_btree_staging.h"
+#include "xfs_icache.h"
+#include "xfs_iunlink_item.h"
+#include "xfs_ag.h"
+#include "xfs_ag_resv.h"
+#include "xfs_error.h"
+#include <linux/iomap.h>
+#include "xfs_iomap.h"
+#include "xfs_buf_mem.h"
+#include "xfs_btree_mem.h"
+#include "xfs_exchmaps.h"
+#include "xfs_exchrange.h"
+#include "xfs_parent.h"
+#include "xfs_rmap.h"
+#include "xfs_refcount.h"
+#include "xfs_metafile.h"
+#include "xfs_metadir.h"
+#include "xfs_rtgroup.h"
+#include "xfs_zone_alloc.h"
+#include "xfs_zone_priv.h"
+#include "xfs_health.h"
+#include "xfs_healthmon.h"
+#include "xfs_notify_failure.h"
+#include "xfs_file.h"
+#include <linux/fserror.h>
+
+/*
+ * We include this last to have the helpers above available for the trace
+ * event implementations.
+ */
+#define CREATE_TRACE_POINTS
+#include "xfs_trace.h"