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/midcomms.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 fs/dlm/midcomms.h (limited to 'fs/dlm/midcomms.h') diff --git a/fs/dlm/midcomms.h b/fs/dlm/midcomms.h new file mode 100644 index 000000000..7fad1d170 --- /dev/null +++ b/fs/dlm/midcomms.h @@ -0,0 +1,42 @@ +/* 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 __MIDCOMMS_DOT_H__ +#define __MIDCOMMS_DOT_H__ + +struct midcomms_node; + +int dlm_validate_incoming_buffer(int nodeid, unsigned char *buf, int len); +int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int buflen); +struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len, char **ppc); +void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh, const void *name, + int namelen); +int dlm_midcomms_addr(int nodeid, struct sockaddr_storage *addr); +void dlm_midcomms_version_wait(void); +int dlm_midcomms_close(int nodeid); +int dlm_midcomms_start(void); +void dlm_midcomms_stop(void); +void dlm_midcomms_init(void); +void dlm_midcomms_exit(void); +void dlm_midcomms_shutdown(void); +void dlm_midcomms_add_member(int nodeid); +void dlm_midcomms_remove_member(int nodeid); +void dlm_midcomms_unack_msg_resend(int nodeid); +const char *dlm_midcomms_state(struct midcomms_node *node); +unsigned long dlm_midcomms_flags(struct midcomms_node *node); +int dlm_midcomms_send_queue_cnt(struct midcomms_node *node); +uint32_t dlm_midcomms_version(struct midcomms_node *node); +int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf, + int buflen); +struct kmem_cache *dlm_midcomms_cache_create(void); + +#endif /* __MIDCOMMS_DOT_H__ */ + -- cgit v1.3.1