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/dlm/lockspace.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 fs/dlm/lockspace.h (limited to 'fs/dlm/lockspace.h') diff --git a/fs/dlm/lockspace.h b/fs/dlm/lockspace.h new file mode 100644 index 000000000..47ebd4411 --- /dev/null +++ b/fs/dlm/lockspace.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/****************************************************************************** +******************************************************************************* +** +** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. +** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. +** +** +******************************************************************************* +******************************************************************************/ + +#ifndef __LOCKSPACE_DOT_H__ +#define __LOCKSPACE_DOT_H__ + +/* DLM_LSFL_FS + * The lockspace user is in the kernel (i.e. filesystem). Enables + * direct bast/cast callbacks. + * + * internal lockspace flag - will be removed in future + */ +#define DLM_LSFL_FS 0x00000004 + +int dlm_lockspace_init(void); +void dlm_lockspace_exit(void); +struct dlm_ls *dlm_find_lockspace_global(uint32_t id); +struct dlm_ls *dlm_find_lockspace_local(void *id); +struct dlm_ls *dlm_find_lockspace_device(int minor); +void dlm_put_lockspace(struct dlm_ls *ls); +void dlm_stop_lockspaces(void); +int dlm_new_user_lockspace(const char *name, const char *cluster, + uint32_t flags, int lvblen, + const struct dlm_lockspace_ops *ops, + void *ops_arg, int *ops_result, + dlm_lockspace_t **lockspace); + +#endif /* __LOCKSPACE_DOT_H__ */ + -- cgit v1.3.1