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/ocfs2/blockcheck.h | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 fs/ocfs2/blockcheck.h (limited to 'fs/ocfs2/blockcheck.h') diff --git a/fs/ocfs2/blockcheck.h b/fs/ocfs2/blockcheck.h new file mode 100644 index 000000000..d0578e98e --- /dev/null +++ b/fs/ocfs2/blockcheck.h @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * blockcheck.h + * + * Checksum and ECC codes for the OCFS2 userspace library. + * + * Copyright (C) 2004, 2008 Oracle. All rights reserved. + */ + +#ifndef OCFS2_BLOCKCHECK_H +#define OCFS2_BLOCKCHECK_H + + +/* Count errors and error correction from blockcheck.c */ +struct ocfs2_blockcheck_stats { + spinlock_t b_lock; + u64 b_check_count; /* Number of blocks we've checked */ + u64 b_failure_count; /* Number of failed checksums */ + u64 b_recover_count; /* Number of blocks fixed by ecc */ + + /* + * debugfs entries, used if this is passed to + * ocfs2_blockcheck_stats_debugfs_install() + */ + struct dentry *b_debug_dir; /* Parent of the debugfs files */ +}; + + +/* High level block API */ +void ocfs2_compute_meta_ecc(struct super_block *sb, void *data, + struct ocfs2_block_check *bc); +int ocfs2_validate_meta_ecc(struct super_block *sb, void *data, + struct ocfs2_block_check *bc); +void ocfs2_compute_meta_ecc_bhs(struct super_block *sb, + struct buffer_head **bhs, int nr, + struct ocfs2_block_check *bc); +int ocfs2_validate_meta_ecc_bhs(struct super_block *sb, + struct buffer_head **bhs, int nr, + struct ocfs2_block_check *bc); + +/* Lower level API */ +void ocfs2_block_check_compute(void *data, size_t blocksize, + struct ocfs2_block_check *bc); +int ocfs2_block_check_validate(void *data, size_t blocksize, + struct ocfs2_block_check *bc, + struct ocfs2_blockcheck_stats *stats); +void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr, + struct ocfs2_block_check *bc); +int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr, + struct ocfs2_block_check *bc, + struct ocfs2_blockcheck_stats *stats); + +/* Debug Initialization */ +void ocfs2_blockcheck_stats_debugfs_install(struct ocfs2_blockcheck_stats *stats, + struct dentry *parent); +void ocfs2_blockcheck_stats_debugfs_remove(struct ocfs2_blockcheck_stats *stats); + +/* + * Hamming code functions + */ + +/* + * Encoding hamming code parity bits for a buffer. + * + * This is the low level encoder function. It can be called across + * multiple hunks just like the crc32 code. 'd' is the number of bits + * _in_this_hunk_. nr is the bit offset of this hunk. So, if you had + * two 512B buffers, you would do it like so: + * + * parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0); + * parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8); + * + * If you just have one buffer, use ocfs2_hamming_encode_block(). + */ +u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d, + unsigned int nr); +/* + * Fix a buffer with a bit error. The 'fix' is the original parity + * xor'd with the parity calculated now. + * + * Like ocfs2_hamming_encode(), this can handle hunks. nr is the bit + * offset of the current hunk. If bit to be fixed is not part of the + * current hunk, this does nothing. + * + * If you only have one buffer, use ocfs2_hamming_fix_block(). + */ +void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr, + unsigned int fix); + +/* Convenience wrappers for a single buffer of data */ +extern u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize); +extern void ocfs2_hamming_fix_block(void *data, unsigned int blocksize, + unsigned int fix); +#endif -- cgit v1.3.1