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/ext2/file.c | 217 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 217 insertions(+) create mode 100644 fs/ext2/file.c (limited to 'fs/ext2/file.c') diff --git a/fs/ext2/file.c b/fs/ext2/file.c new file mode 100644 index 000000000..b9020df7d --- /dev/null +++ b/fs/ext2/file.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/ext2/file.c + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/fs/minix/file.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * ext2 fs regular file handling primitives + * + * 64-bit file support on 64-bit platforms by Jakub Jelinek + * (jj@sunsite.ms.mff.cuni.cz) + */ + +#include +#include +#include +#include +#include +#include +#include +#include "ext2.h" +#include "xattr.h" +#include "acl.h" +#include "trace.h" + + +/* + * Called when filp is released. This happens when all file descriptors + * for a single struct file are closed. Note that different open() calls + * for the same file yield different struct file structures. + */ +static int ext2_release_file (struct inode * inode, struct file * filp) +{ + if (filp->f_mode & FMODE_WRITE) { + mutex_lock(&EXT2_I(inode)->truncate_mutex); + ext2_discard_reservation(inode); + mutex_unlock(&EXT2_I(inode)->truncate_mutex); + } + return 0; +} + +static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + ssize_t ret; + + trace_ext2_dio_read_begin(iocb, to, 0); + inode_lock_shared(inode); + ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0); + inode_unlock_shared(inode); + trace_ext2_dio_read_end(iocb, to, ret); + + return ret; +} + +static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size, + int error, unsigned int flags) +{ + loff_t pos = iocb->ki_pos; + struct inode *inode = file_inode(iocb->ki_filp); + + if (error) + goto out; + + /* + * If we are extending the file, we have to update i_size here before + * page cache gets invalidated in iomap_dio_rw(). This prevents racing + * buffered reads from zeroing out too much from page cache pages. + * Note that all extending writes always happens synchronously with + * inode lock held by ext2_dio_write_iter(). So it is safe to update + * inode size here for extending file writes. + */ + pos += size; + if (pos > i_size_read(inode)) { + i_size_write(inode, pos); + mark_inode_dirty(inode); + } +out: + trace_ext2_dio_write_endio(iocb, size, error); + return error; +} + +static const struct iomap_dio_ops ext2_dio_write_ops = { + .end_io = ext2_dio_write_end_io, +}; + +static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + ssize_t ret; + unsigned int flags = 0; + unsigned long blocksize = inode->i_sb->s_blocksize; + loff_t offset = iocb->ki_pos; + loff_t count = iov_iter_count(from); + ssize_t status = 0; + + trace_ext2_dio_write_begin(iocb, from, 0); + inode_lock(inode); + ret = generic_write_checks(iocb, from); + if (ret <= 0) + goto out_unlock; + + ret = kiocb_modified(iocb); + if (ret) + goto out_unlock; + + /* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */ + if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) || + (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize))) + flags |= IOMAP_DIO_FORCE_WAIT; + + ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops, + flags, NULL, 0); + + /* ENOTBLK is magic return value for fallback to buffered-io */ + if (ret == -ENOTBLK) + ret = 0; + + if (ret < 0 && ret != -EIOCBQUEUED) + ext2_write_failed(inode->i_mapping, offset + count); + + /* handle case for partial write and for fallback to buffered write */ + if (ret >= 0 && iov_iter_count(from)) { + loff_t pos, endbyte; + int ret2; + + iocb->ki_flags &= ~IOCB_DIRECT; + pos = iocb->ki_pos; + status = generic_perform_write(iocb, from); + if (unlikely(status < 0)) { + ret = status; + goto out_unlock; + } + + ret += status; + endbyte = pos + status - 1; + ret2 = filemap_write_and_wait_range(inode->i_mapping, pos, + endbyte); + if (!ret2) { + invalidate_mapping_pages(inode->i_mapping, + pos >> PAGE_SHIFT, + endbyte >> PAGE_SHIFT); + if (ret > 0) + ret = generic_write_sync(iocb, ret); + } else { + ret = ret2; + } + } + +out_unlock: + inode_unlock(inode); + if (status) + trace_ext2_dio_write_buff_end(iocb, from, status); + trace_ext2_dio_write_end(iocb, from, ret); + return ret; +} + +static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + if (iocb->ki_flags & IOCB_DIRECT) + return ext2_dio_read_iter(iocb, to); + + return generic_file_read_iter(iocb, to); +} + +static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + if (iocb->ki_flags & IOCB_DIRECT) + return ext2_dio_write_iter(iocb, from); + + return generic_file_write_iter(iocb, from); +} + +static int ext2_file_open(struct inode *inode, struct file *filp) +{ + filp->f_mode |= FMODE_CAN_ODIRECT; + return dquot_file_open(inode, filp); +} + +const struct file_operations ext2_file_operations = { + .llseek = generic_file_llseek, + .read_iter = ext2_file_read_iter, + .write_iter = ext2_file_write_iter, + .unlocked_ioctl = ext2_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = ext2_compat_ioctl, +#endif + .mmap_prepare = generic_file_mmap_prepare, + .open = ext2_file_open, + .release = ext2_release_file, + .fsync = simple_fsync, + .get_unmapped_area = thp_get_unmapped_area, + .splice_read = filemap_splice_read, + .splice_write = iter_file_splice_write, + .setlease = generic_setlease, +}; + +const struct inode_operations ext2_file_inode_operations = { + .listxattr = ext2_listxattr, + .getattr = ext2_getattr, + .setattr = ext2_setattr, + .get_inode_acl = ext2_get_acl, + .set_acl = ext2_set_acl, + .fiemap = ext2_fiemap, + .fileattr_get = ext2_fileattr_get, + .fileattr_set = ext2_fileattr_set, +}; -- cgit v1.3.1