From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock 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 Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- fs/lockd/nlm.h | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 fs/lockd/nlm.h (limited to 'fs/lockd/nlm.h') diff --git a/fs/lockd/nlm.h b/fs/lockd/nlm.h new file mode 100644 index 000000000..47be65d01 --- /dev/null +++ b/fs/lockd/nlm.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Declarations for the Network Lock Manager protocol. + * + * Copyright (C) 1996, Olaf Kirch + */ + +#ifndef _LOCKD_NLM_H +#define _LOCKD_NLM_H + + +/* Maximum file offset in file_lock.fl_end */ +# define NLM_OFFSET_MAX ((s32) 0x7fffffff) +# define NLM4_OFFSET_MAX ((s64) ((~(u64)0) >> 1)) + +/* Return states for NLM */ +enum { + NLM_LCK_GRANTED = 0, + NLM_LCK_DENIED = 1, + NLM_LCK_DENIED_NOLOCKS = 2, + NLM_LCK_BLOCKED = 3, + NLM_LCK_DENIED_GRACE_PERIOD = 4, +#ifdef CONFIG_LOCKD_V4 + NLM_DEADLCK = 5, + NLM_ROFS = 6, + NLM_STALE_FH = 7, + NLM_FBIG = 8, + NLM_FAILED = 9, +#endif +}; + +#define NLM_PROGRAM 100021 + +#define NLMPROC_NULL 0 +#define NLMPROC_TEST 1 +#define NLMPROC_LOCK 2 +#define NLMPROC_CANCEL 3 +#define NLMPROC_UNLOCK 4 +#define NLMPROC_GRANTED 5 +#define NLMPROC_TEST_MSG 6 +#define NLMPROC_LOCK_MSG 7 +#define NLMPROC_CANCEL_MSG 8 +#define NLMPROC_UNLOCK_MSG 9 +#define NLMPROC_GRANTED_MSG 10 +#define NLMPROC_TEST_RES 11 +#define NLMPROC_LOCK_RES 12 +#define NLMPROC_CANCEL_RES 13 +#define NLMPROC_UNLOCK_RES 14 +#define NLMPROC_GRANTED_RES 15 +#define NLMPROC_NSM_NOTIFY 16 /* statd callback */ +#define NLMPROC_SHARE 20 +#define NLMPROC_UNSHARE 21 +#define NLMPROC_NM_LOCK 22 +#define NLMPROC_FREE_ALL 23 + +#endif /* _LOCKD_NLM_H */ -- cgit v1.3.1