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 --- drivers/md/dm-rq.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 drivers/md/dm-rq.h (limited to 'drivers/md/dm-rq.h') diff --git a/drivers/md/dm-rq.h b/drivers/md/dm-rq.h new file mode 100644 index 000000000..1f73e194e --- /dev/null +++ b/drivers/md/dm-rq.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Internal header file for device mapper + * + * Copyright (C) 2016 Red Hat, Inc. All rights reserved. + * + * This file is released under the LGPL. + */ + +#ifndef DM_RQ_INTERNAL_H +#define DM_RQ_INTERNAL_H + +#include +#include + +#include "dm-stats.h" + +struct mapped_device; + +/* + * For request-based dm - the bio clones we allocate are embedded in these + * structs. + * + * We allocate these with bio_alloc_bioset, using the front_pad parameter when + * the bioset is created - this means the bio has to come at the end of the + * struct. + */ +struct dm_rq_clone_bio_info { + struct bio *orig; + struct dm_rq_target_io *tio; + struct bio clone; +}; + +int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t); +void dm_mq_cleanup_mapped_device(struct mapped_device *md); + +void dm_start_queue(struct request_queue *q); +void dm_stop_queue(struct request_queue *q); + +void dm_mq_kick_requeue_list(struct mapped_device *md); + +unsigned int dm_get_reserved_rq_based_ios(void); + +ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf); +ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md, + const char *buf, size_t count); + +#endif -- cgit v1.3.1