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/bfs/dir.c | 356 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 356 insertions(+) create mode 100644 fs/bfs/dir.c (limited to 'fs/bfs/dir.c') diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c new file mode 100644 index 000000000..91a4871fa --- /dev/null +++ b/fs/bfs/dir.c @@ -0,0 +1,356 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/bfs/dir.c + * BFS directory operations. + * Copyright (C) 1999-2018 Tigran Aivazian + * Made endianness-clean by Andrew Stribblehill 2005 + */ + +#include +#include +#include +#include +#include +#include "bfs.h" + +#undef DEBUG + +#ifdef DEBUG +#define dprintf(x...) printf(x) +#else +#define dprintf(x...) +#endif + +static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino); +static struct buffer_head *bfs_find_entry(struct inode *dir, + const struct qstr *child, + struct bfs_dirent **res_dir); + +static int bfs_readdir(struct file *f, struct dir_context *ctx) +{ + struct inode *dir = file_inode(f); + struct buffer_head *bh; + struct bfs_dirent *de; + unsigned int offset; + int block; + + if (ctx->pos & (BFS_DIRENT_SIZE - 1)) { + printf("Bad f_pos=%08lx for %s:%08llx\n", + (unsigned long)ctx->pos, + dir->i_sb->s_id, dir->i_ino); + return -EINVAL; + } + + while (ctx->pos < dir->i_size) { + offset = ctx->pos & (BFS_BSIZE - 1); + block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS); + bh = sb_bread(dir->i_sb, block); + if (!bh) { + ctx->pos += BFS_BSIZE - offset; + continue; + } + do { + de = (struct bfs_dirent *)(bh->b_data + offset); + if (de->ino) { + int size = strnlen(de->name, BFS_NAMELEN); + if (!dir_emit(ctx, de->name, size, + le16_to_cpu(de->ino), + DT_UNKNOWN)) { + brelse(bh); + return 0; + } + } + offset += BFS_DIRENT_SIZE; + ctx->pos += BFS_DIRENT_SIZE; + } while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size)); + brelse(bh); + } + return 0; +} + +const struct file_operations bfs_dir_operations = { + .read = generic_read_dir, + .iterate_shared = bfs_readdir, + .fsync = simple_fsync, + .llseek = generic_file_llseek, +}; + +static int bfs_create(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + int err; + struct inode *inode; + struct super_block *s = dir->i_sb; + struct bfs_sb_info *info = BFS_SB(s); + unsigned long ino; + + inode = new_inode(s); + if (!inode) + return -ENOMEM; + mutex_lock(&info->bfs_lock); + ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1); + if (ino > info->si_lasti) { + mutex_unlock(&info->bfs_lock); + iput(inode); + return -ENOSPC; + } + set_bit(ino, info->si_imap); + info->si_freei--; + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); + simple_inode_init_ts(inode); + inode->i_blocks = 0; + inode->i_op = &bfs_file_inops; + inode->i_fop = &bfs_file_operations; + inode->i_mapping->a_ops = &bfs_aops; + inode->i_ino = ino; + BFS_I(inode)->i_dsk_ino = ino; + BFS_I(inode)->i_sblock = 0; + BFS_I(inode)->i_eblock = 0; + insert_inode_hash(inode); + mark_inode_dirty(inode); + bfs_dump_imap("create", s); + + err = bfs_add_entry(dir, &dentry->d_name, inode->i_ino); + if (err) { + inode_dec_link_count(inode); + mutex_unlock(&info->bfs_lock); + iput(inode); + return err; + } + mutex_unlock(&info->bfs_lock); + d_instantiate(dentry, inode); + return 0; +} + +static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct inode *inode = NULL; + struct buffer_head *bh; + struct bfs_dirent *de; + struct bfs_sb_info *info = BFS_SB(dir->i_sb); + + if (dentry->d_name.len > BFS_NAMELEN) + return ERR_PTR(-ENAMETOOLONG); + + mutex_lock(&info->bfs_lock); + bh = bfs_find_entry(dir, &dentry->d_name, &de); + if (bh) { + unsigned long ino = (unsigned long)le16_to_cpu(de->ino); + brelse(bh); + inode = bfs_iget(dir->i_sb, ino); + } + mutex_unlock(&info->bfs_lock); + return d_splice_alias(inode, dentry); +} + +static int bfs_link(struct dentry *old, struct inode *dir, + struct dentry *new) +{ + struct inode *inode = d_inode(old); + struct bfs_sb_info *info = BFS_SB(inode->i_sb); + int err; + + mutex_lock(&info->bfs_lock); + err = bfs_add_entry(dir, &new->d_name, inode->i_ino); + if (err) { + mutex_unlock(&info->bfs_lock); + return err; + } + inc_nlink(inode); + inode_set_ctime_current(inode); + mark_inode_dirty(inode); + ihold(inode); + d_instantiate(new, inode); + mutex_unlock(&info->bfs_lock); + return 0; +} + +static int bfs_unlink(struct inode *dir, struct dentry *dentry) +{ + int error = -ENOENT; + struct inode *inode = d_inode(dentry); + struct buffer_head *bh; + struct bfs_dirent *de; + struct bfs_sb_info *info = BFS_SB(inode->i_sb); + + mutex_lock(&info->bfs_lock); + bh = bfs_find_entry(dir, &dentry->d_name, &de); + if (!bh || (le16_to_cpu(de->ino) != inode->i_ino)) + goto out_brelse; + + if (!inode->i_nlink) { + printf("unlinking non-existent file %s:%llu (nlink=%d)\n", + inode->i_sb->s_id, inode->i_ino, + inode->i_nlink); + set_nlink(inode, 1); + } + de->ino = 0; + mmb_mark_buffer_dirty(bh, &BFS_I(dir)->i_metadata_bhs); + inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); + mark_inode_dirty(dir); + inode_set_ctime_to_ts(inode, inode_get_ctime(dir)); + inode_dec_link_count(inode); + error = 0; + +out_brelse: + brelse(bh); + mutex_unlock(&info->bfs_lock); + return error; +} + +static int bfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, + struct dentry *old_dentry, struct inode *new_dir, + struct dentry *new_dentry, unsigned int flags) +{ + struct inode *old_inode, *new_inode; + struct buffer_head *old_bh, *new_bh; + struct bfs_dirent *old_de, *new_de; + struct bfs_sb_info *info; + int error = -ENOENT; + + if (flags & ~RENAME_NOREPLACE) + return -EINVAL; + + old_bh = new_bh = NULL; + old_inode = d_inode(old_dentry); + if (S_ISDIR(old_inode->i_mode)) + return -EINVAL; + + info = BFS_SB(old_inode->i_sb); + + mutex_lock(&info->bfs_lock); + old_bh = bfs_find_entry(old_dir, &old_dentry->d_name, &old_de); + + if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino)) + goto end_rename; + + error = -EPERM; + new_inode = d_inode(new_dentry); + new_bh = bfs_find_entry(new_dir, &new_dentry->d_name, &new_de); + + if (new_bh && !new_inode) { + brelse(new_bh); + new_bh = NULL; + } + if (!new_bh) { + error = bfs_add_entry(new_dir, &new_dentry->d_name, + old_inode->i_ino); + if (error) + goto end_rename; + } + old_de->ino = 0; + inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir)); + mark_inode_dirty(old_dir); + if (new_inode) { + inode_set_ctime_current(new_inode); + inode_dec_link_count(new_inode); + } + mmb_mark_buffer_dirty(old_bh, &BFS_I(old_dir)->i_metadata_bhs); + error = 0; + +end_rename: + mutex_unlock(&info->bfs_lock); + brelse(old_bh); + brelse(new_bh); + return error; +} + +const struct inode_operations bfs_dir_inops = { + .create = bfs_create, + .lookup = bfs_lookup, + .link = bfs_link, + .unlink = bfs_unlink, + .rename = bfs_rename, +}; + +static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino) +{ + const unsigned char *name = child->name; + int namelen = child->len; + struct buffer_head *bh; + struct bfs_dirent *de; + int block, sblock, eblock, off, pos; + int i; + + dprintf("name=%s, namelen=%d\n", name, namelen); + + sblock = BFS_I(dir)->i_sblock; + eblock = BFS_I(dir)->i_eblock; + for (block = sblock; block <= eblock; block++) { + bh = sb_bread(dir->i_sb, block); + if (!bh) + return -EIO; + for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) { + de = (struct bfs_dirent *)(bh->b_data + off); + if (!de->ino) { + pos = (block - sblock) * BFS_BSIZE + off; + if (pos >= dir->i_size) { + dir->i_size += BFS_DIRENT_SIZE; + inode_set_ctime_current(dir); + } + inode_set_mtime_to_ts(dir, + inode_set_ctime_current(dir)); + mark_inode_dirty(dir); + de->ino = cpu_to_le16((u16)ino); + for (i = 0; i < BFS_NAMELEN; i++) + de->name[i] = + (i < namelen) ? name[i] : 0; + mmb_mark_buffer_dirty(bh, + &BFS_I(dir)->i_metadata_bhs); + brelse(bh); + return 0; + } + } + brelse(bh); + } + return -ENOSPC; +} + +static inline int bfs_namecmp(int len, const unsigned char *name, + const char *buffer) +{ + if ((len < BFS_NAMELEN) && buffer[len]) + return 0; + return !memcmp(name, buffer, len); +} + +static struct buffer_head *bfs_find_entry(struct inode *dir, + const struct qstr *child, + struct bfs_dirent **res_dir) +{ + unsigned long block = 0, offset = 0; + struct buffer_head *bh = NULL; + struct bfs_dirent *de; + const unsigned char *name = child->name; + int namelen = child->len; + + *res_dir = NULL; + if (namelen > BFS_NAMELEN) + return NULL; + + while (block * BFS_BSIZE + offset < dir->i_size) { + if (!bh) { + bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); + if (!bh) { + block++; + continue; + } + } + de = (struct bfs_dirent *)(bh->b_data + offset); + offset += BFS_DIRENT_SIZE; + if (le16_to_cpu(de->ino) && + bfs_namecmp(namelen, name, de->name)) { + *res_dir = de; + return bh; + } + if (offset < bh->b_size) + continue; + brelse(bh); + bh = NULL; + offset = 0; + block++; + } + brelse(bh); + return NULL; +} -- cgit v1.3.1