{"api_version":"1","generated_at":"2026-09-18T05:19:03+00:00","cve":"CVE-2026-92501","urls":{"html":"https://cve.report/CVE-2026-92501","api":"https://cve.report/api/cve/CVE-2026-92501.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-92501","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-92501"},"summary":{"title":"ext4: drain in-flight DIO before buffered write fallback","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: drain in-flight DIO before buffered write fallback\n\ngeneric/746 started failing intermittently on ext3 (no-extent inodes).\nThe test triggers 'Page cache invalidation failure on direct I/O'\nwarnings and subsequent fsync returns -EIO. Adding a 50ms delay\nbetween ext4_buffered_write_iter() and filemap_write_and_wait_range()\nin ext4_dio_write_iter() makes the race almost always reproducible.\n\nOn no-extent inodes, DIO writes to holes cannot use unwritten extents,\nso ext4_iomap_alloc() leaves m_flags=0 and ext4_map_blocks() returns 0.\nThe iomap layer then returns -ENOTBLK, causing fallback to buffered I/O.\n\nThe fallback path in ext4_dio_write_iter() calls\next4_buffered_write_iter() which dirties pages, then does flush and\ninvalidate. However, there's an unprotected window between\next4_buffered_write_iter() returning (with inode lock released) and\nthe subsequent flush+invalidate.\n\nConcurrent async DIO completions from other threads can run\nkiocb_invalidate_post_direct_write() during this window. If pages have\nbeen re-dirtied, post-invalidation finds dirty pages and triggers the\nwarning, setting -EIO in the error sequence.\n\nConsider a file with two 4k extents: [hole][written]. Thread A does\nDIO to the written extent, while thread B does DIO spanning both:\n\n  kworker A (4k DIO, allocated block)    kworker B (8k DIO, fallback)\n  -----------------------------------    ----------------------------\n  inode_lock_shared()                    inode_lock_shared()\n  iomap_dio_rw():                        iomap_dio_rw():\n    kiocb_invalidate_pages -> clean        iomap_begin -> -ENOTBLK\n    submit_bio (async)                     dio->size = 0\n  inode_unlock_shared()                  inode_unlock_shared()\n\n  [bio pending in block layer]           /* fallback: lock released */\n                                         ext4_buffered_write_iter()\n                                           inode_lock(exclusive)\n                                           generic_perform_write()\n                                             -> dirty pages [0, 8k]\n                                           inode_unlock(exclusive)\n\n                                         /* pages dirty, no lock */\n  [bio completes]                        filemap_write_and_wait_range()\n  iomap_dio_complete()                     -> flush dirty pages\n    kiocb_invalidate_post_direct_write() invalidate_mapping_pages()\n      invalidate_inode_pages2_range()\n      -> finds dirty page!\n      -> dio_warn_stale_pagecache()\n      -> errseq_set(-EIO)\n\nThis issue can be triggered through normal I/O paths, not just\nintentionally overlapping DIO writes from userspace. For example,\ngeneric/746 uses a loop device where multiple kworkers issue concurrent\nI/O to the backing file. Additionally, when block_size < folio_size,\nnon-overlapping DIO writes that share a large folio can also trigger\nthe race.\n\nAdd inode_dio_wait() in ext4_buffered_write_iter() before\next4_write_checks() to drain all in-flight DIO. This ensures that\nall DIO clears existing pages before submitting IO (via\nkiocb_invalidate_pages()), all BIO waits for all DIO to complete\n(via inode_dio_wait()), and ext4_write_checks() observes the inode\nsize after all completed DIO so that ext4_block_zero_eof() does not\nrace with in-flight DIO, thus eliminating the race.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-17 17:17:52","updated_at":"2026-09-17 17:17:52"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/9fd3ffc3c51c9deaba99bd7b338fff2d08f52416","name":"https://git.kernel.org/stable/c/9fd3ffc3c51c9deaba99bd7b338fff2d08f52416","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/74eee4ff9698a65b2e6e15dac0e50d6526ad5f20","name":"https://git.kernel.org/stable/c/74eee4ff9698a65b2e6e15dac0e50d6526ad5f20","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4e4e3eec506247c8f8bd8aaa1eb25e67016681a5","name":"https://git.kernel.org/stable/c/4e4e3eec506247c8f8bd8aaa1eb25e67016681a5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f0af3ae09fb72382da1a5371bf6761b0264668e4","name":"https://git.kernel.org/stable/c/f0af3ae09fb72382da1a5371bf6761b0264668e4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7341e234927ff215f1d5d0bcfe04b74f53af378d","name":"https://git.kernel.org/stable/c/7341e234927ff215f1d5d0bcfe04b74f53af378d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/15cdefd0c0522f9d5e12d947fa04f4c11649b699","name":"https://git.kernel.org/stable/c/15cdefd0c0522f9d5e12d947fa04f4c11649b699","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fd7e0dab20837b9ea1eeef7c26f78ace8ac8258c","name":"https://git.kernel.org/stable/c/fd7e0dab20837b9ea1eeef7c26f78ace8ac8258c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d47cdadd6e49023f7ee248048463807f1214f1ee","name":"https://git.kernel.org/stable/c/d47cdadd6e49023f7ee248048463807f1214f1ee","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-92501","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-92501","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 fd7e0dab20837b9ea1eeef7c26f78ace8ac8258c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 f0af3ae09fb72382da1a5371bf6761b0264668e4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 7341e234927ff215f1d5d0bcfe04b74f53af378d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 74eee4ff9698a65b2e6e15dac0e50d6526ad5f20 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 d47cdadd6e49023f7ee248048463807f1214f1ee git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 4e4e3eec506247c8f8bd8aaa1eb25e67016681a5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 9fd3ffc3c51c9deaba99bd7b338fff2d08f52416 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 378f32bab3714f04c4e0c3aee4129f6703805550 15cdefd0c0522f9d5e12d947fa04f4c11649b699 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.5","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.270 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.221 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.188 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.157 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.110 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.52 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.6 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/ext4/file.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"fd7e0dab20837b9ea1eeef7c26f78ace8ac8258c","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"f0af3ae09fb72382da1a5371bf6761b0264668e4","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"7341e234927ff215f1d5d0bcfe04b74f53af378d","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"74eee4ff9698a65b2e6e15dac0e50d6526ad5f20","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"d47cdadd6e49023f7ee248048463807f1214f1ee","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"4e4e3eec506247c8f8bd8aaa1eb25e67016681a5","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"9fd3ffc3c51c9deaba99bd7b338fff2d08f52416","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"},{"lessThan":"15cdefd0c0522f9d5e12d947fa04f4c11649b699","status":"affected","version":"378f32bab3714f04c4e0c3aee4129f6703805550","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/ext4/file.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.5"},{"lessThan":"5.5","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.270","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.221","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.188","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.157","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.110","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.52","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.270","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.221","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.188","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.110","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.52","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.6","versionStartIncluding":"5.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"5.5","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: drain in-flight DIO before buffered write fallback\n\ngeneric/746 started failing intermittently on ext3 (no-extent inodes).\nThe test triggers 'Page cache invalidation failure on direct I/O'\nwarnings and subsequent fsync returns -EIO. Adding a 50ms delay\nbetween ext4_buffered_write_iter() and filemap_write_and_wait_range()\nin ext4_dio_write_iter() makes the race almost always reproducible.\n\nOn no-extent inodes, DIO writes to holes cannot use unwritten extents,\nso ext4_iomap_alloc() leaves m_flags=0 and ext4_map_blocks() returns 0.\nThe iomap layer then returns -ENOTBLK, causing fallback to buffered I/O.\n\nThe fallback path in ext4_dio_write_iter() calls\next4_buffered_write_iter() which dirties pages, then does flush and\ninvalidate. However, there's an unprotected window between\next4_buffered_write_iter() returning (with inode lock released) and\nthe subsequent flush+invalidate.\n\nConcurrent async DIO completions from other threads can run\nkiocb_invalidate_post_direct_write() during this window. If pages have\nbeen re-dirtied, post-invalidation finds dirty pages and triggers the\nwarning, setting -EIO in the error sequence.\n\nConsider a file with two 4k extents: [hole][written]. Thread A does\nDIO to the written extent, while thread B does DIO spanning both:\n\n  kworker A (4k DIO, allocated block)    kworker B (8k DIO, fallback)\n  -----------------------------------    ----------------------------\n  inode_lock_shared()                    inode_lock_shared()\n  iomap_dio_rw():                        iomap_dio_rw():\n    kiocb_invalidate_pages -> clean        iomap_begin -> -ENOTBLK\n    submit_bio (async)                     dio->size = 0\n  inode_unlock_shared()                  inode_unlock_shared()\n\n  [bio pending in block layer]           /* fallback: lock released */\n                                         ext4_buffered_write_iter()\n                                           inode_lock(exclusive)\n                                           generic_perform_write()\n                                             -> dirty pages [0, 8k]\n                                           inode_unlock(exclusive)\n\n                                         /* pages dirty, no lock */\n  [bio completes]                        filemap_write_and_wait_range()\n  iomap_dio_complete()                     -> flush dirty pages\n    kiocb_invalidate_post_direct_write() invalidate_mapping_pages()\n      invalidate_inode_pages2_range()\n      -> finds dirty page!\n      -> dio_warn_stale_pagecache()\n      -> errseq_set(-EIO)\n\nThis issue can be triggered through normal I/O paths, not just\nintentionally overlapping DIO writes from userspace. For example,\ngeneric/746 uses a loop device where multiple kworkers issue concurrent\nI/O to the backing file. Additionally, when block_size < folio_size,\nnon-overlapping DIO writes that share a large folio can also trigger\nthe race.\n\nAdd inode_dio_wait() in ext4_buffered_write_iter() before\next4_write_checks() to drain all in-flight DIO. This ensures that\nall DIO clears existing pages before submitting IO (via\nkiocb_invalidate_pages()), all BIO waits for all DIO to complete\n(via inode_dio_wait()), and ext4_write_checks() observes the inode\nsize after all completed DIO so that ext4_block_zero_eof() does not\nrace with in-flight DIO, thus eliminating the race."}],"providerMetadata":{"dateUpdated":"2026-09-17T16:10:14.753Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/fd7e0dab20837b9ea1eeef7c26f78ace8ac8258c"},{"url":"https://git.kernel.org/stable/c/f0af3ae09fb72382da1a5371bf6761b0264668e4"},{"url":"https://git.kernel.org/stable/c/7341e234927ff215f1d5d0bcfe04b74f53af378d"},{"url":"https://git.kernel.org/stable/c/74eee4ff9698a65b2e6e15dac0e50d6526ad5f20"},{"url":"https://git.kernel.org/stable/c/d47cdadd6e49023f7ee248048463807f1214f1ee"},{"url":"https://git.kernel.org/stable/c/4e4e3eec506247c8f8bd8aaa1eb25e67016681a5"},{"url":"https://git.kernel.org/stable/c/9fd3ffc3c51c9deaba99bd7b338fff2d08f52416"},{"url":"https://git.kernel.org/stable/c/15cdefd0c0522f9d5e12d947fa04f4c11649b699"}],"title":"ext4: drain in-flight DIO before buffered write fallback","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-92501","datePublished":"2026-09-17T16:10:14.753Z","dateReserved":"2026-09-16T12:21:13.871Z","dateUpdated":"2026-09-17T16:10:14.753Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-17 17:17:52","lastModifiedDate":"2026-09-17 17:17:52","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"92501","Ordinal":"1","Title":"ext4: drain in-flight DIO before buffered write fallback","CVE":"CVE-2026-92501","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"92501","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: drain in-flight DIO before buffered write fallback\n\ngeneric/746 started failing intermittently on ext3 (no-extent inodes).\nThe test triggers 'Page cache invalidation failure on direct I/O'\nwarnings and subsequent fsync returns -EIO. Adding a 50ms delay\nbetween ext4_buffered_write_iter() and filemap_write_and_wait_range()\nin ext4_dio_write_iter() makes the race almost always reproducible.\n\nOn no-extent inodes, DIO writes to holes cannot use unwritten extents,\nso ext4_iomap_alloc() leaves m_flags=0 and ext4_map_blocks() returns 0.\nThe iomap layer then returns -ENOTBLK, causing fallback to buffered I/O.\n\nThe fallback path in ext4_dio_write_iter() calls\next4_buffered_write_iter() which dirties pages, then does flush and\ninvalidate. However, there's an unprotected window between\next4_buffered_write_iter() returning (with inode lock released) and\nthe subsequent flush+invalidate.\n\nConcurrent async DIO completions from other threads can run\nkiocb_invalidate_post_direct_write() during this window. If pages have\nbeen re-dirtied, post-invalidation finds dirty pages and triggers the\nwarning, setting -EIO in the error sequence.\n\nConsider a file with two 4k extents: [hole][written]. Thread A does\nDIO to the written extent, while thread B does DIO spanning both:\n\n  kworker A (4k DIO, allocated block)    kworker B (8k DIO, fallback)\n  -----------------------------------    ----------------------------\n  inode_lock_shared()                    inode_lock_shared()\n  iomap_dio_rw():                        iomap_dio_rw():\n    kiocb_invalidate_pages -> clean        iomap_begin -> -ENOTBLK\n    submit_bio (async)                     dio->size = 0\n  inode_unlock_shared()                  inode_unlock_shared()\n\n  [bio pending in block layer]           /* fallback: lock released */\n                                         ext4_buffered_write_iter()\n                                           inode_lock(exclusive)\n                                           generic_perform_write()\n                                             -> dirty pages [0, 8k]\n                                           inode_unlock(exclusive)\n\n                                         /* pages dirty, no lock */\n  [bio completes]                        filemap_write_and_wait_range()\n  iomap_dio_complete()                     -> flush dirty pages\n    kiocb_invalidate_post_direct_write() invalidate_mapping_pages()\n      invalidate_inode_pages2_range()\n      -> finds dirty page!\n      -> dio_warn_stale_pagecache()\n      -> errseq_set(-EIO)\n\nThis issue can be triggered through normal I/O paths, not just\nintentionally overlapping DIO writes from userspace. For example,\ngeneric/746 uses a loop device where multiple kworkers issue concurrent\nI/O to the backing file. Additionally, when block_size < folio_size,\nnon-overlapping DIO writes that share a large folio can also trigger\nthe race.\n\nAdd inode_dio_wait() in ext4_buffered_write_iter() before\next4_write_checks() to drain all in-flight DIO. This ensures that\nall DIO clears existing pages before submitting IO (via\nkiocb_invalidate_pages()), all BIO waits for all DIO to complete\n(via inode_dio_wait()), and ext4_write_checks() observes the inode\nsize after all completed DIO so that ext4_block_zero_eof() does not\nrace with in-flight DIO, thus eliminating the race.","Type":"Description","Title":"ext4: drain in-flight DIO before buffered write fallback"}]}}}