CVE-2025-68821

/// Technical description

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

fuse: fix readahead reclaim deadlock

Commit e26ee4efbc79 ("fuse: allocate ff->release_args only if release is

needed") skips allocating ff->release_args if the server does not

implement open. However in doing so, fuse_prepare_release() now skips

grabbing the reference on the inode, which makes it possible for an

inode to be evicted from the dcache while there are inflight readahead

requests. This causes a deadlock if the server triggers reclaim while

servicing the readahead request and reclaim attempts to evict the inode

of the file being read ahead. Since the folio is locked during

readahead, when reclaim evicts the fuse inode and fuse_evict_inode()

attempts to remove all folios associated with the inode from the page

cache (truncate_inode_pages_range()), reclaim will block forever waiting

for the lock since readahead cannot relinquish the lock because it is

itself blocked in reclaim:

>>> stack_trace(1504735)

foli

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References