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, 138 insertions, 0 deletions

diff --git a/fs/afs/afs_vl.h b/fs/afs/afs_vl.h
new file mode 100644
index 000000000..b835e25a2
--- /dev/null
+++ b/fs/afs/afs_vl.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* AFS Volume Location Service client interface
+ *
+ * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef AFS_VL_H
+#define AFS_VL_H
+
+#include "afs.h"
+
+#define AFS_VL_PORT		7003	/* volume location service port */
+#define VL_SERVICE		52	/* RxRPC service ID for the Volume Location service */
+#define YFS_VL_SERVICE		2503	/* Service ID for AuriStor upgraded VL service */
+#define YFS_VL_MAXCELLNAME	256  	/* Maximum length of a cell name in YFS protocol */
+
+enum AFSVL_Operations {
+	VLGETENTRYBYID		= 503,	/* AFS Get VLDB entry by ID */
+	VLGETENTRYBYNAME	= 504,	/* AFS Get VLDB entry by name */
+	VLPROBE			= 514,	/* AFS probe VL service */
+	VLGETENTRYBYIDU		= 526,	/* AFS Get VLDB entry by ID (UUID-variant) */
+	VLGETENTRYBYNAMEU	= 527,	/* AFS Get VLDB entry by name (UUID-variant) */
+	VLGETADDRSU		= 533,	/* AFS Get addrs for fileserver */
+	YVLGETENDPOINTS		= 64002, /* YFS Get endpoints for file/volume server */
+	YVLGETCELLNAME		= 64014, /* YFS Get actual cell name */
+	VLGETCAPABILITIES	= 65537, /* AFS Get server capabilities */
+};
+
+enum AFSVL_Errors {
+	AFSVL_IDEXIST 		= 363520,	/* Volume Id entry exists in vl database */
+	AFSVL_IO 		= 363521,	/* I/O related error */
+	AFSVL_NAMEEXIST 	= 363522,	/* Volume name entry exists in vl database */
+	AFSVL_CREATEFAIL 	= 363523,	/* Internal creation failure */
+	AFSVL_NOENT 		= 363524,	/* No such entry */
+	AFSVL_EMPTY 		= 363525,	/* Vl database is empty */
+	AFSVL_ENTDELETED 	= 363526,	/* Entry is deleted (soft delete) */
+	AFSVL_BADNAME 		= 363527,	/* Volume name is illegal */
+	AFSVL_BADINDEX 		= 363528,	/* Index is out of range */
+	AFSVL_BADVOLTYPE 	= 363529,	/* Bad volume type */
+	AFSVL_BADSERVER 	= 363530,	/* Illegal server number (out of range) */
+	AFSVL_BADPARTITION 	= 363531,	/* Bad partition number */
+	AFSVL_REPSFULL 		= 363532,	/* Run out of space for Replication sites */
+	AFSVL_NOREPSERVER 	= 363533,	/* No such Replication server site exists */
+	AFSVL_DUPREPSERVER 	= 363534,	/* Replication site already exists */
+	AFSVL_RWNOTFOUND 	= 363535,	/* Parent R/W entry not found */
+	AFSVL_BADREFCOUNT 	= 363536,	/* Illegal Reference Count number */
+	AFSVL_SIZEEXCEEDED 	= 363537,	/* Vl size for attributes exceeded */
+	AFSVL_BADENTRY 		= 363538,	/* Bad incoming vl entry */
+	AFSVL_BADVOLIDBUMP 	= 363539,	/* Illegal max volid increment */
+	AFSVL_IDALREADYHASHED 	= 363540,	/* RO/BACK id already hashed */
+	AFSVL_ENTRYLOCKED 	= 363541,	/* Vl entry is already locked */
+	AFSVL_BADVOLOPER 	= 363542,	/* Bad volume operation code */
+	AFSVL_BADRELLOCKTYPE 	= 363543,	/* Bad release lock type */
+	AFSVL_RERELEASE 	= 363544,	/* Status report: last release was aborted */
+	AFSVL_BADSERVERFLAG 	= 363545,	/* Invalid replication site server flag */
+	AFSVL_PERM 		= 363546,	/* No permission access */
+	AFSVL_NOMEM 		= 363547,	/* malloc/realloc failed to alloc enough memory */
+};
+
+enum {
+	YFS_SERVER_INDEX	= 0,
+	YFS_SERVER_UUID		= 1,
+	YFS_SERVER_ENDPOINT	= 2,
+};
+
+enum {
+	YFS_ENDPOINT_IPV4	= 0,
+	YFS_ENDPOINT_IPV6	= 1,
+};
+
+#define YFS_MAXENDPOINTS	16
+
+/*
+ * maps to "struct vldbentry" in vvl-spec.pdf
+ */
+struct afs_vldbentry {
+	char		name[65];		/* name of volume (with NUL char) */
+	afs_voltype_t	type;			/* volume type */
+	unsigned	num_servers;		/* num servers that hold instances of this vol */
+	unsigned	clone_id;		/* cloning ID */
+
+	unsigned	flags;
+#define AFS_VLF_RWEXISTS	0x1000		/* R/W volume exists */
+#define AFS_VLF_ROEXISTS	0x2000		/* R/O volume exists */
+#define AFS_VLF_BACKEXISTS	0x4000		/* backup volume exists */
+
+	afs_volid_t	volume_ids[3];		/* volume IDs */
+
+	struct {
+		struct in_addr	addr;		/* server address */
+		unsigned	partition;	/* partition ID on this server */
+		unsigned	flags;		/* server specific flags */
+#define AFS_VLSF_NEWREPSITE	0x0001	/* Ignore all 'non-new' servers */
+#define AFS_VLSF_ROVOL		0x0002	/* this server holds a R/O instance of the volume */
+#define AFS_VLSF_RWVOL		0x0004	/* this server holds a R/W instance of the volume */
+#define AFS_VLSF_BACKVOL	0x0008	/* this server holds a backup instance of the volume */
+#define AFS_VLSF_UUID		0x0010	/* This server is referred to by its UUID */
+#define AFS_VLSF_DONTUSE	0x0020	/* This server ref should be ignored */
+	} servers[8];
+};
+
+#define AFS_VLDB_MAXNAMELEN 65
+
+
+struct afs_ListAddrByAttributes__xdr {
+	__be32			Mask;
+#define AFS_VLADDR_IPADDR	0x1	/* Match by ->ipaddr */
+#define AFS_VLADDR_INDEX	0x2	/* Match by ->index */
+#define AFS_VLADDR_UUID		0x4	/* Match by ->uuid */
+	__be32			ipaddr;
+	__be32			index;
+	__be32			spare;
+	struct afs_uuid__xdr	uuid;
+};
+
+struct afs_uvldbentry__xdr {
+	__be32			name[AFS_VLDB_MAXNAMELEN];
+	__be32			nServers;
+	struct afs_uuid__xdr	serverNumber[AFS_NMAXNSERVERS];
+	__be32			serverUnique[AFS_NMAXNSERVERS];
+	__be32			serverPartition[AFS_NMAXNSERVERS];
+	__be32			serverFlags[AFS_NMAXNSERVERS];
+	__be32			volumeId[AFS_MAXTYPES];
+	__be32			cloneId;
+	__be32			flags;
+	__be32			spares1;
+	__be32			spares2;
+	__be32			spares3;
+	__be32			spares4;
+	__be32			spares5;
+	__be32			spares6;
+	__be32			spares7;
+	__be32			spares8;
+	__be32			spares9;
+};
+
+#endif /* AFS_VL_H */