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/xfs_exchrange.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 fs/xfs/xfs_exchrange.h (limited to 'fs/xfs/xfs_exchrange.h') diff --git a/fs/xfs/xfs_exchrange.h b/fs/xfs/xfs_exchrange.h new file mode 100644 index 000000000..bc1298aba --- /dev/null +++ b/fs/xfs/xfs_exchrange.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (c) 2020-2024 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#ifndef __XFS_EXCHRANGE_H__ +#define __XFS_EXCHRANGE_H__ + +/* Update the mtime/cmtime of file1 and file2 */ +#define __XFS_EXCHANGE_RANGE_UPD_CMTIME1 (1ULL << 63) +#define __XFS_EXCHANGE_RANGE_UPD_CMTIME2 (1ULL << 62) + +/* Freshness check required */ +#define __XFS_EXCHANGE_RANGE_CHECK_FRESH2 (1ULL << 61) + +#define XFS_EXCHANGE_RANGE_PRIV_FLAGS (__XFS_EXCHANGE_RANGE_UPD_CMTIME1 | \ + __XFS_EXCHANGE_RANGE_UPD_CMTIME2 | \ + __XFS_EXCHANGE_RANGE_CHECK_FRESH2) + +struct xfs_exchrange { + struct file *file1; + struct file *file2; + + loff_t file1_offset; + loff_t file2_offset; + u64 length; + + u64 flags; /* XFS_EXCHANGE_RANGE flags */ + + /* file2 metadata for freshness checks */ + u64 file2_ino; + struct timespec64 file2_mtime; + struct timespec64 file2_ctime; + u32 file2_gen; +}; + +long xfs_ioc_exchange_range(struct file *file, + struct xfs_exchange_range __user *argp); +long xfs_ioc_start_commit(struct file *file, + struct xfs_commit_range __user *argp); +long xfs_ioc_commit_range(struct file *file, + struct xfs_commit_range __user *argp); + +struct xfs_exchmaps_req; + +void xfs_exchrange_ilock(struct xfs_trans *tp, struct xfs_inode *ip1, + struct xfs_inode *ip2); +void xfs_exchrange_iunlock(struct xfs_inode *ip1, struct xfs_inode *ip2); + +int xfs_exchrange_estimate(struct xfs_exchmaps_req *req); + +#endif /* __XFS_EXCHRANGE_H__ */ -- cgit v1.3.1