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, 86 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/status-codes.h b/drivers/md/dm-vdo/status-codes.h
new file mode 100644
index 000000000..426dc8e2c
--- /dev/null
+++ b/drivers/md/dm-vdo/status-codes.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_STATUS_CODES_H
+#define VDO_STATUS_CODES_H
+
+#include "errors.h"
+
+enum {
+	UDS_ERRORS_BLOCK_SIZE = UDS_ERROR_CODE_BLOCK_END - UDS_ERROR_CODE_BASE,
+	VDO_ERRORS_BLOCK_START = UDS_ERROR_CODE_BLOCK_END,
+	VDO_ERRORS_BLOCK_END = VDO_ERRORS_BLOCK_START + UDS_ERRORS_BLOCK_SIZE,
+};
+
+/* VDO-specific status codes. */
+enum vdo_status_codes {
+	/* base of all VDO errors */
+	VDO_STATUS_CODE_BASE = VDO_ERRORS_BLOCK_START,
+	/* we haven't written this yet */
+	VDO_NOT_IMPLEMENTED = VDO_STATUS_CODE_BASE,
+	/* input out of range */
+	VDO_OUT_OF_RANGE,
+	/* an invalid reference count would result */
+	VDO_REF_COUNT_INVALID,
+	/* a free block could not be allocated */
+	VDO_NO_SPACE,
+	/* improper or missing configuration option */
+	VDO_BAD_CONFIGURATION,
+	/* prior operation still in progress */
+	VDO_COMPONENT_BUSY,
+	/* page contents incorrect or corrupt data */
+	VDO_BAD_PAGE,
+	/* unsupported version of some component */
+	VDO_UNSUPPORTED_VERSION,
+	/* component id mismatch in decoder */
+	VDO_INCORRECT_COMPONENT,
+	/* parameters have conflicting values */
+	VDO_PARAMETER_MISMATCH,
+	/* no partition exists with a given id */
+	VDO_UNKNOWN_PARTITION,
+	/* a partition already exists with a given id */
+	VDO_PARTITION_EXISTS,
+	/* physical block growth of too few blocks */
+	VDO_INCREMENT_TOO_SMALL,
+	/* incorrect checksum */
+	VDO_CHECKSUM_MISMATCH,
+	/* a lock is held incorrectly */
+	VDO_LOCK_ERROR,
+	/* the VDO is in read-only mode */
+	VDO_READ_ONLY,
+	/* the VDO is shutting down */
+	VDO_SHUTTING_DOWN,
+	/* the recovery journal has corrupt entries or corrupt metadata */
+	VDO_CORRUPT_JOURNAL,
+	/* exceeds maximum number of slabs supported */
+	VDO_TOO_MANY_SLABS,
+	/* a compressed block fragment is invalid */
+	VDO_INVALID_FRAGMENT,
+	/* action is unsupported while rebuilding */
+	VDO_RETRY_AFTER_REBUILD,
+	/* a block map entry is invalid */
+	VDO_BAD_MAPPING,
+	/* bio_add_page failed */
+	VDO_BIO_CREATION_FAILED,
+	/* bad magic number */
+	VDO_BAD_MAGIC,
+	/* bad nonce */
+	VDO_BAD_NONCE,
+	/* sequence number overflow */
+	VDO_JOURNAL_OVERFLOW,
+	/* the VDO is not in a state to perform an admin operation */
+	VDO_INVALID_ADMIN_STATE,
+	/* one more than last error code */
+	VDO_STATUS_CODE_LAST,
+	VDO_STATUS_CODE_BLOCK_END = VDO_ERRORS_BLOCK_END
+};
+
+extern const struct error_info vdo_status_list[];
+
+int vdo_register_status_codes(void);
+
+int vdo_status_to_errno(int error);
+
+#endif /* VDO_STATUS_CODES_H */