From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- fs/verity/pagecache.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 fs/verity/pagecache.c (limited to 'fs/verity/pagecache.c') diff --git a/fs/verity/pagecache.c b/fs/verity/pagecache.c new file mode 100644 index 000000000..99f5f53ee --- /dev/null +++ b/fs/verity/pagecache.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2019 Google LLC + */ +#include "fsverity_private.h" + +#include +#include +#include + +/** + * generic_read_merkle_tree_page - generic ->read_merkle_tree_page helper + * @inode: inode containing the Merkle tree + * @index: 0-based index of the Merkle tree page in the inode + * + * The caller needs to adjust @index from the Merkle-tree relative index passed + * to ->read_merkle_tree_page to the actual index where the Merkle tree is + * stored in the page cache for @inode. + */ +struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index) +{ + struct folio *folio; + + folio = read_mapping_folio(inode->i_mapping, index, NULL); + if (IS_ERR(folio)) + return ERR_CAST(folio); + return folio_file_page(folio, index); +} +EXPORT_SYMBOL_GPL(generic_read_merkle_tree_page); + +/** + * generic_readahead_merkle_tree() - generic ->readahead_merkle_tree helper + * @inode: inode containing the Merkle tree + * @index: 0-based index of the first Merkle tree page to read ahead in the + * inode + * @nr_pages: the number of Merkle tree pages that should be read ahead + * + * The caller needs to adjust @index from the Merkle-tree relative index passed + * to ->read_merkle_tree_page to the actual index where the Merkle tree is + * stored in the page cache for @inode. + */ +void generic_readahead_merkle_tree(struct inode *inode, pgoff_t index, + unsigned long nr_pages) +{ + struct folio *folio; + + lockdep_assert_held(&inode->i_mapping->invalidate_lock); + + folio = __filemap_get_folio(inode->i_mapping, index, FGP_ACCESSED, 0); + if (folio == ERR_PTR(-ENOENT) || + (!IS_ERR(folio) && !folio_test_uptodate(folio))) { + DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index); + + page_cache_ra_unbounded(&ractl, nr_pages, 0); + } + if (!IS_ERR(folio)) + folio_put(folio); +} +EXPORT_SYMBOL_GPL(generic_readahead_merkle_tree); + +/** + * fsverity_fill_zerohash() - fill folio with hashes of zero data block + * @folio: folio to fill + * @offset: offset in the folio to start + * @len: length of the range to fill with hashes + * @vi: fsverity info + */ +void fsverity_fill_zerohash(struct folio *folio, size_t offset, size_t len, + struct fsverity_info *vi) +{ + size_t off = offset; + + WARN_ON_ONCE(!IS_ALIGNED(offset, vi->tree_params.digest_size)); + WARN_ON_ONCE(!IS_ALIGNED(len, vi->tree_params.digest_size)); + + for (; off < (offset + len); off += vi->tree_params.digest_size) + memcpy_to_folio(folio, off, vi->tree_params.zero_digest, + vi->tree_params.digest_size); +} +EXPORT_SYMBOL_GPL(fsverity_fill_zerohash); -- cgit v1.3.1