{"id":"CVE-2026-98920","state":"PUBLISHED","title":"netfs: Fix missing alloc tagging of direct mempool allocations","description":"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 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.","publishedAt":"2026-10-23T12:02:06.560Z","updatedAt":"2026-10-23T12:05:25.919Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"15ed8a9b7c63e9171f5139a6aaa1ffb61809861f","status":"affected","lessThan":"5c03da745171485fd181f17b69213464f6d05f3d","versionType":"git"},{"version":"1d78d56c43ef3768183e8370e7367b162700e049","status":"affected","lessThan":"37a2042748bc880df03ff8315db86ed82991fbb8","versionType":"git"},{"version":"1d78d56c43ef3768183e8370e7367b162700e049","status":"affected","lessThan":"b78b728e21c32ec4c330b299f657fb1eb02dffc2","versionType":"git"},{"version":"b343252d6f536203dd0660f676190dcbf6d2ecdc","status":"affected","versionType":"git"},{"version":"3f6d7f8a5416d852648d15a05e895f1195ee8a85","status":"affected","versionType":"git"},{"version":"6.12.114","status":"affected","lessThan":"6.13","versionType":"semver"},{"version":"7.1.8","status":"affected","lessThan":"7.2","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/objects.c","fs/netfs/rolling_buffer.c","include/linux/mempool.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.2","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/objects.c","fs/netfs/rolling_buffer.c","include/linux/mempool.h"]}],"references":["https://git.kernel.org/stable/c/5c03da745171485fd181f17b69213464f6d05f3d","https://git.kernel.org/stable/c/37a2042748bc880df03ff8315db86ed82991fbb8","https://git.kernel.org/stable/c/b78b728e21c32ec4c330b299f657fb1eb02dffc2"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98920.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98920","state":"PUBLISHED","datePublished":"2026-10-23T12:02:06.560Z","dateUpdated":"2026-10-23T12:05:25.919Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.380Z"},"containers":{"cna":{"title":"netfs: Fix missing alloc tagging of direct mempool allocations","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"15ed8a9b7c63e9171f5139a6aaa1ffb61809861f","status":"affected","lessThan":"5c03da745171485fd181f17b69213464f6d05f3d","versionType":"git"},{"version":"1d78d56c43ef3768183e8370e7367b162700e049","status":"affected","lessThan":"37a2042748bc880df03ff8315db86ed82991fbb8","versionType":"git"},{"version":"1d78d56c43ef3768183e8370e7367b162700e049","status":"affected","lessThan":"b78b728e21c32ec4c330b299f657fb1eb02dffc2","versionType":"git"},{"version":"b343252d6f536203dd0660f676190dcbf6d2ecdc","status":"affected","versionType":"git"},{"version":"3f6d7f8a5416d852648d15a05e895f1195ee8a85","status":"affected","versionType":"git"},{"version":"6.12.114","status":"affected","lessThan":"6.13","versionType":"semver"},{"version":"7.1.8","status":"affected","lessThan":"7.2","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/objects.c","fs/netfs/rolling_buffer.c","include/linux/mempool.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.2","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/objects.c","fs/netfs/rolling_buffer.c","include/linux/mempool.h"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-23T12:05:25.919Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1.8"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}