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/aops.h | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 fs/ocfs2/aops.h (limited to 'fs/ocfs2/aops.h') diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h new file mode 100644 index 000000000..114efc911 --- /dev/null +++ b/fs/ocfs2/aops.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2002, 2004, 2005 Oracle. All rights reserved. + */ + +#ifndef OCFS2_AOPS_H +#define OCFS2_AOPS_H + +#include + +int ocfs2_map_folio_blocks(struct folio *folio, u64 *p_blkno, + struct inode *inode, unsigned int from, + unsigned int to, int new); + +void ocfs2_unlock_and_free_folios(struct folio **folios, int num_folios); + +int walk_page_buffers( handle_t *handle, + struct buffer_head *head, + unsigned from, + unsigned to, + int *partial, + int (*fn)( handle_t *handle, + struct buffer_head *bh)); + +int ocfs2_write_end_nolock(struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, void *fsdata); + +typedef enum { + OCFS2_WRITE_BUFFER = 0, + OCFS2_WRITE_DIRECT, + OCFS2_WRITE_MMAP, +} ocfs2_write_type_t; + +int ocfs2_write_begin_nolock(struct address_space *mapping, + loff_t pos, unsigned len, ocfs2_write_type_t type, + struct folio **foliop, void **fsdata, + struct buffer_head *di_bh, struct folio *mmap_folio); + +int ocfs2_read_inline_data(struct inode *inode, struct folio *folio, + struct buffer_head *di_bh); +int ocfs2_size_fits_inline_data(struct buffer_head *di_bh, u64 new_size); + +int ocfs2_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh_result, int create); +/* all ocfs2_dio_end_io()'s fault */ +#define ocfs2_iocb_is_rw_locked(iocb) \ + test_bit(0, (unsigned long *)&iocb->private) +static inline void ocfs2_iocb_set_rw_locked(struct kiocb *iocb, int level) +{ + set_bit(0, (unsigned long *)&iocb->private); + if (level) + set_bit(1, (unsigned long *)&iocb->private); + else + clear_bit(1, (unsigned long *)&iocb->private); +} + +/* + * Using a named enum representing lock types in terms of #N bit stored in + * iocb->private, which is going to be used for communication between + * ocfs2_dio_end_io() and ocfs2_file_write/read_iter(). + */ +enum ocfs2_iocb_lock_bits { + OCFS2_IOCB_RW_LOCK = 0, + OCFS2_IOCB_RW_LOCK_LEVEL, + OCFS2_IOCB_NUM_LOCKS +}; + +#define ocfs2_iocb_init_rw_locked(iocb) \ + (iocb->private = NULL) +#define ocfs2_iocb_clear_rw_locked(iocb) \ + clear_bit(OCFS2_IOCB_RW_LOCK, (unsigned long *)&iocb->private) +#define ocfs2_iocb_rw_locked_level(iocb) \ + test_bit(OCFS2_IOCB_RW_LOCK_LEVEL, (unsigned long *)&iocb->private) + +#endif /* OCFS2_FILE_H */ -- cgit v1.3.1