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/xfs/scrub/bitmap.h | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 fs/xfs/scrub/bitmap.h (limited to 'fs/xfs/scrub/bitmap.h') diff --git a/fs/xfs/scrub/bitmap.h b/fs/xfs/scrub/bitmap.h new file mode 100644 index 000000000..710c1ac5e --- /dev/null +++ b/fs/xfs/scrub/bitmap.h @@ -0,0 +1,67 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2018-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#ifndef __XFS_SCRUB_BITMAP_H__ +#define __XFS_SCRUB_BITMAP_H__ + +/* u64 bitmap */ + +struct xbitmap64 { + struct rb_root_cached xb_root; +}; + +void xbitmap64_init(struct xbitmap64 *bitmap); +void xbitmap64_destroy(struct xbitmap64 *bitmap); + +int xbitmap64_clear(struct xbitmap64 *bitmap, uint64_t start, uint64_t len); +int xbitmap64_set(struct xbitmap64 *bitmap, uint64_t start, uint64_t len); +int xbitmap64_disunion(struct xbitmap64 *bitmap, struct xbitmap64 *sub); +uint64_t xbitmap64_hweight(struct xbitmap64 *bitmap); + +/* + * Return codes for the bitmap iterator functions are 0 to continue iterating, + * and non-zero to stop iterating. Any non-zero value will be passed up to the + * iteration caller. The special value -ECANCELED can be used to stop + * iteration, because neither bitmap iterator ever generates that error code on + * its own. Callers must not modify the bitmap while walking it. + */ +typedef int (*xbitmap64_walk_fn)(uint64_t start, uint64_t len, void *priv); +int xbitmap64_walk(struct xbitmap64 *bitmap, xbitmap64_walk_fn fn, + void *priv); + +bool xbitmap64_empty(struct xbitmap64 *bitmap); +bool xbitmap64_test(struct xbitmap64 *bitmap, uint64_t start, uint64_t *len); + +/* u32 bitmap */ + +struct xbitmap32 { + struct rb_root_cached xb_root; +}; + +void xbitmap32_init(struct xbitmap32 *bitmap); +void xbitmap32_destroy(struct xbitmap32 *bitmap); + +int xbitmap32_clear(struct xbitmap32 *bitmap, uint32_t start, uint32_t len); +int xbitmap32_set(struct xbitmap32 *bitmap, uint32_t start, uint32_t len); +int xbitmap32_disunion(struct xbitmap32 *bitmap, struct xbitmap32 *sub); +uint32_t xbitmap32_hweight(struct xbitmap32 *bitmap); + +/* + * Return codes for the bitmap iterator functions are 0 to continue iterating, + * and non-zero to stop iterating. Any non-zero value will be passed up to the + * iteration caller. The special value -ECANCELED can be used to stop + * iteration, because neither bitmap iterator ever generates that error code on + * its own. Callers must not modify the bitmap while walking it. + */ +typedef int (*xbitmap32_walk_fn)(uint32_t start, uint32_t len, void *priv); +int xbitmap32_walk(struct xbitmap32 *bitmap, xbitmap32_walk_fn fn, + void *priv); + +bool xbitmap32_empty(struct xbitmap32 *bitmap); +bool xbitmap32_test(struct xbitmap32 *bitmap, uint32_t start, uint32_t *len); + +uint32_t xbitmap32_count_set_regions(struct xbitmap32 *bitmap); + +#endif /* __XFS_SCRUB_BITMAP_H__ */ -- cgit v1.3.1