CVE-2025-68821 : 詳細

CVE-2025-68821

0.03%V4
2026-01-13
15h29 +00:00
2026-02-09
08h34 +00:00
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CVE の説明

fuse: fix readahead reclaim deadlock

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()).

CVE の情報

EPSS

EPSSは脆弱性が悪用される可能性を予測するスコアリングモデルです。

EPSSスコア

EPSSモデルは0から1(0〜100%)の確率スコアを算出します。スコアが高いほど、脆弱性が悪用される可能性が高いことを示します。

EPSSパーセンタイル

パーセンタイルはCVEをEPSSスコアで順位付けするために使用されます。例えば、EPSSスコアで95パーセンタイルにあるCVEは、他の95%のCVEよりも悪用される可能性が高いことを意味します。パーセンタイルはCVEのEPSSスコアを他のCVEと比較するために使用されます。

参考資料