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/nilfs2/page.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 fs/nilfs2/page.h (limited to 'fs/nilfs2/page.h') diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h new file mode 100644 index 000000000..136cd1c14 --- /dev/null +++ b/fs/nilfs2/page.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Buffer/page management specific to NILFS + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * Written by Ryusuke Konishi and Seiji Kihara. + */ + +#ifndef _NILFS_PAGE_H +#define _NILFS_PAGE_H + +#include +#include "nilfs.h" + +/* + * Extended buffer state bits + */ +enum { + BH_NILFS_Allocated = BH_PrivateStart, + BH_NILFS_Node, + BH_NILFS_Volatile, + BH_NILFS_Checked, + BH_NILFS_Redirected, +}; + +BUFFER_FNS(NILFS_Node, nilfs_node) /* nilfs node buffers */ +BUFFER_FNS(NILFS_Volatile, nilfs_volatile) +BUFFER_FNS(NILFS_Checked, nilfs_checked) /* buffer is verified */ +BUFFER_FNS(NILFS_Redirected, nilfs_redirected) /* redirected to a copy */ + + +void __nilfs_clear_folio_dirty(struct folio *); + +struct buffer_head *nilfs_grab_buffer(struct inode *, struct address_space *, + unsigned long, unsigned long); +void nilfs_forget_buffer(struct buffer_head *); +void nilfs_copy_buffer(struct buffer_head *, struct buffer_head *); +bool nilfs_folio_buffers_clean(struct folio *); +void nilfs_folio_bug(struct folio *); + +int nilfs_copy_dirty_pages(struct address_space *, struct address_space *); +void nilfs_copy_back_pages(struct address_space *, struct address_space *); +void nilfs_clear_folio_dirty(struct folio *folio); +void nilfs_clear_dirty_pages(struct address_space *mapping); +unsigned int nilfs_page_count_clean_buffers(struct folio *folio, + unsigned int from, unsigned int to); +unsigned long nilfs_find_uncommitted_extent(struct inode *inode, + sector_t start_blk, + sector_t *blkoff); + +#define NILFS_FOLIO_BUG(folio, m, a...) \ + do { nilfs_folio_bug(folio); BUG(); } while (0) + +#endif /* _NILFS_PAGE_H */ -- cgit v1.3.1