[LTP] cve: reproducer for cve-2026-64600

[linuxtestproject.agent@gmail.com]

Hi Andrea,

On August 1, 2026, Andrea Cervesato wrote:
> cve: reproducer for cve-2026-64600

> 	struct stat sb;
>
> 	SAFE_STAT(".", &sb);
> 	blksize = sb.st_blksize;

Could the I/O size and alignment be derived from MNTPOINT or TARGET instead?
The framework mounts XFS at MNTPOINT but leaves "." on the surrounding
temporary filesystem, whose block size can differ from that of XFS.

For example, with a 1 KiB host filesystem and a 4 KiB XFS filesystem, these
writes are not XFS-block-aligned. xfs_file_dio_write_unaligned() returns
-ENOTBLK for the reflinked file, and xfs_file_write_iter() silently retries
the operation as buffered I/O. SAFE_PWRITE() still succeeds, but the test can
then report TPASS without exercising xfs_direct_write_iomap_begin() or the
target race.

Verdict - Needs revision

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LTP AI Reviewer