In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix uninitialized value in ocfs2_file_read_iter()

Syzbot has reported the following KMSAN splat:

BUG: KMSAN: uninit-value in ocfs2_file_read_iter+0x9a4/0xf80
ocfs2_file_read_iter+0x9a4/0xf80
__io_read+0x8d4/0x20f0
io_read+0x3e/0xf0
io_issue_sqe+0x42b/0x22c0
io_wq_submit_work+0xaf9/0xdc0
io_worker_handle_work+0xd13/0x2110
io_wq_worker+0x447/0x1410
ret_from_fork+0x6f/0x90
ret_from_fork_asm+0x1a/0x30

Uninit was created at:
__alloc_pages_noprof+0x9a7/0xe00
alloc_pages_mpol_noprof+0x299/0x990
alloc_pages_noprof+0x1bf/0x1e0
allocate_slab+0x33a/0x1250
___slab_alloc+0x12ef/0x35e0
kmem_cache_alloc_bulk_noprof+0x486/0x1330
__io_alloc_req_refill+0x84/0x560
io_submit_sqes+0x172f/0x2f30
__se_sys_io_uring_enter+0x406/0x41c0
__x64_sys_io_uring_enter+0x11f/0x1a0
x64_sys_call+0x2b54/0x3ba0
do_syscall_64+0xcd/0x1e0
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Since an instance of 'struct kiocb' may be passed from the block layer
with 'private' field uninitialized, introduce 'ocfs2_iocb_init_rw_locked()'
and use it from where 'ocfs2_dio_end_io()' might take care, i.e. in
'ocfs2_file_read_iter()' and 'ocfs2_file_write_iter()'.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-53155
• https://git.kernel.org/stable/c/366c933c2ab34dd6551acc03b4872726b7605143
• https://git.kernel.org/stable/c/66b7ddd1804e2c4216dd7ead8eeb746cdbb3b62f
• https://git.kernel.org/stable/c/6c8f8d1e595dabd5389817f6d798cc8bd95c40ab
• https://git.kernel.org/stable/c/83f8713a0ef1d55d6a287bcfadcaab8245ac5098
• https://git.kernel.org/stable/c/8c966150d5abff58c3c2bdb9a6e63fd773782905
• https://git.kernel.org/stable/c/8e0de82ed18ba0e71f817adbd81317fd1032ca5a
• https://git.kernel.org/stable/c/adc77b19f62d7e80f98400b2fca9d700d2afdd6f
• https://git.kernel.org/stable/c/dc78efe556fed162d48736ef24066f42e463e27c
• https://git.kernel.org/stable/c/f4078ef38d3163e6be47403a619558b19c4bfccd