{"id":"CVE-2026-98920","title":"netfs: Fix missing alloc tagging of direct mempool allocations","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix missing alloc tagging of direct mempool allocations\n\nCommit 1d78d56c43ef (\"netfs: Fix folio_queue ENOMEM in writeback by\nadding a mempool\") added a mempool f…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 15ed8a9b7c63e9171f5139a6aaa1ffb61809861f < 5c03da745171485fd181f17b69213464f6d05f3d","Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 < 37a2042748bc880df03ff8315db86ed82991fbb8","Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 < b78b728e21c32ec4c330b299f657fb1eb02dffc2","Linux b343252d6f536203dd0660f676190dcbf6d2ecdc","Linux 3f6d7f8a5416d852648d15a05e895f1195ee8a85","Linux >= 6.12.114 < 6.13","Linux >= 7.1.8 < 7.2","Linux 7.2"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:05:25.919Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98920","references":[{"url":"https://git.kernel.org/stable/c/5c03da745171485fd181f17b69213464f6d05f3d"},{"url":"https://git.kernel.org/stable/c/37a2042748bc880df03ff8315db86ed82991fbb8"},{"url":"https://git.kernel.org/stable/c/b78b728e21c32ec4c330b299f657fb1eb02dffc2"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.570Z","slug":"CVE-2026-98920","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix missing alloc tagging of direct mempool allocations\n\nCommit 1d78d56c43ef (\"netfs: Fix folio_queue ENOMEM in writeback by\nadding a mempool\") added a mempool for the folio_queues and made the\nrequest, subrequest and folio_queue allocations distinguish between\nwriteback and everything else.  Writeback is part of memory reclaim\nand must not fail due to ENOMEM, so it allocates under GFP_NOFS\nthrough mempool_alloc(), which may dip into the pool's reserve and,\nif that runs empty, wait for elements to be returned.  The\nGFP_KERNEL paths, which can return -ENOMEM to their callers, invoke\nthe pool's ->alloc() callback directly instead.\n\nThe direct call, however, skips the alloc_hooks() wrapper that the\nmempool_alloc() macro provides.  The pool callbacks, mempool_alloc_slab()\nand mempool_kmalloc(), call kmem_cache_alloc_noprof() and kmalloc_noprof()\nand rely on current->alloc_tag having been set by the caller.  With\nCONFIG_MEM_ALLOC_PROFILING_DEBUG=y this leads to\n\n    current->alloc_tag not set\n    WARNING: ./include/linux/alloc_tag.h:161 at __alloc_tagging_slab_alloc_hook\n    alloc_tag was not set\n    WARNING: ./include/linux/alloc_tag.h:166 at __alloc_tagging_slab_free_hook\n\nat allocation and free time respectively, as reported when reading\nfiles on a CIFS mount.  The allocations are also missing from\n/proc/allocinfo.\n\nWrap the direct ->alloc() invocations in alloc_hooks() with a new\nmempool_alloc_noreserve() helper in include/linux/mempool.h, next to\nthe other alloc_hooks()-wrapped macros such as mempool_alloc().  The\nGFP_KERNEL paths keep their failable allocation semantics, they just\nget tagged now.\n\n## Affected\n\n- `Linux >= 15ed8a9b7c63e9171f5139a6aaa1ffb61809861f < 5c03da745171485fd181f17b69213464f6d05f3d`\n- `Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 < 37a2042748bc880df03ff8315db86ed82991fbb8`\n- `Linux >= 1d78d56c43ef3768183e8370e7367b162700e049 < b78b728e21c32ec4c330b299f657fb1eb02dffc2`\n- `Linux b343252d6f536203dd0660f676190dcbf6d2ecdc`\n- `Linux 3f6d7f8a5416d852648d15a05e895f1195ee8a85`\n- `Linux >= 6.12.114 < 6.13`\n- `Linux >= 7.1.8 < 7.2`\n- `Linux 7.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}