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1dedde6903
It is possible for i_disksize can exceed i_size, triggering a warning.
generic_perform_write
copied = iov_iter_copy_from_user_atomic(len) // copied < len
ext4_da_write_end
| ext4_update_i_disksize
| new_i_size = pos + copied;
| WRITE_ONCE(EXT4_I(inode)->i_disksize, newsize) // update i_disksize
| generic_write_end
| copied = block_write_end(copied, len) // copied = 0
| if (unlikely(copied < len))
| if (!PageUptodate(page))
| copied = 0;
| if (pos + copied > inode->i_size) // return false
if (unlikely(copied == 0))
goto again;
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
We get i_disksize greater than i_size here, which could trigger WARNING
check 'i_size_read(inode) < EXT4_I(inode)->i_disksize' while doing dio:
ext4_dio_write_iter
iomap_dio_rw
__iomap_dio_rw // return err, length is not aligned to 512
ext4_handle_inode_extension
WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize) // Oops
WARNING: CPU: 2 PID: 2609 at fs/ext4/file.c:319
CPU: 2 PID: 2609 Comm: aa Not tainted 6.3.0-rc2
RIP: 0010:ext4_file_write_iter+0xbc7
Call Trace:
vfs_write+0x3b1
ksys_write+0x77
do_syscall_64+0x39
Fix it by updating 'copied' value before updating i_disksize just like
ext4_write_inline_data_end() does.
A reproducer can be found in the buganizer link below.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217209
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.