{"id":"CVE-2025-37999","state":"PUBLISHED","title":"fs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()\n\nIf bio_add_folio() fails (because it is full),\nerofs_fileio_scan_folio() needs to submit the I/O request via\nerofs_fileio_rq_submit() and allocate a new I/O request with an empty\n`struct bio`.  Then it retries the bio_add_folio() call.\n\nHowever, at this point, erofs_onlinefolio_split() has already been\ncalled which increments `folio->private`; the retry will call\nerofs_onlinefolio_split() again, but there will never be a matching\nerofs_onlinefolio_end() call.  This leaves the folio locked forever\nand all waiters will be stuck in folio_wait_bit_common().\n\nThis bug has been added by commit ce63cb62d794 (\"erofs: support\nunencoded inodes for fileio\"), but was practically unreachable because\nthere was room for 256 folios in the `struct bio` - until commit\n9f74ae8c9ac9 (\"erofs: shorten bvecs[] for file-backed mounts\") which\nreduced the array capacity to 16 folios.\n\nIt was now trivial to trigger the bug by manually invoking readahead\nfrom userspace, e.g.:\n\n posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED);\n\nThis should be fixed by invoking erofs_onlinefolio_split() only after\nbio_add_folio() has succeeded.  This is safe: asynchronous completions\ninvoking erofs_onlinefolio_end() will not unlock the folio because\nerofs_fileio_scan_folio() is still holding a reference to be released\nby erofs_onlinefolio_end() at the end.","publishedAt":"2025-05-29T13:15:56.825Z","updatedAt":"2026-05-11T21:19:21.337Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ce63cb62d794c98c7631c2296fa845f2a8d0a4a1","status":"affected","lessThan":"61e0fc3312309867e5a3495329dad0286d2a5703","versionType":"git"},{"version":"ce63cb62d794c98c7631c2296fa845f2a8d0a4a1","status":"affected","lessThan":"c26076197df348c84cc23e5962d61902e072a0f5","versionType":"git"},{"version":"ce63cb62d794c98c7631c2296fa845f2a8d0a4a1","status":"affected","lessThan":"bbfe756dc3062c1e934f06e5ba39c239aa953b92","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/erofs/fileio.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.29","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.14.7","status":"unaffected","lessThanOrEqual":"6.14.*","versionType":"semver"},{"version":"6.15","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/erofs/fileio.c"]}],"references":["https://git.kernel.org/stable/c/61e0fc3312309867e5a3495329dad0286d2a5703","https://git.kernel.org/stable/c/c26076197df348c84cc23e5962d61902e072a0f5","https://git.kernel.org/stable/c/bbfe756dc3062c1e934f06e5ba39c239aa953b92"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:03.054Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/37xxx/CVE-2025-37999.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37999","state":"PUBLISHED","datePublished":"2025-05-29T13:15:56.825Z","dateUpdated":"2026-05-11T21:19:21.337Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T04:51:23.976Z"},"containers":{"cna":{"title":"fs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()\n\nIf bio_add_folio() fails (because it is full),\nerofs_fileio_scan_folio() needs to submit the I/O request via\nerofs_fileio_rq_submit() and allocate a new I/O request with an empty\n`struct bio`.  Then it retries the bio_add_folio() call.\n\nHowever, at this point, erofs_onlinefolio_split() has already been\ncalled which increments `folio->private`; the retry will call\nerofs_onlinefolio_split() again, but there will never be a matching\nerofs_onlinefolio_end() call.  This leaves the folio locked forever\nand all waiters will be stuck in folio_wait_bit_common().\n\nThis bug has been added by commit ce63cb62d794 (\"erofs: support\nunencoded inodes for fileio\"), but was practically unreachable because\nthere was room for 256 folios in the `struct bio` - until commit\n9f74ae8c9ac9 (\"erofs: shorten bvecs[] for file-backed mounts\") which\nreduced the array capacity to 16 folios.\n\nIt was now trivial to trigger the bug by manually invoking readahead\nfrom userspace, e.g.:\n\n posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED);\n\nThis should be fixed by invoking erofs_onlinefolio_split() only after\nbio_add_folio() has succeeded.  This is safe: asynchronous completions\ninvoking erofs_onlinefolio_end() will not unlock the folio because\nerofs_fileio_scan_folio() is still holding a reference to be released\nby erofs_onlinefolio_end() at the end."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ce63cb62d794c98c7631c2296fa845f2a8d0a4a1","status":"affected","lessThan":"61e0fc3312309867e5a3495329dad0286d2a5703","versionType":"git"},{"version":"ce63cb62d794c98c7631c2296fa845f2a8d0a4a1","status":"affected","lessThan":"c26076197df348c84cc23e5962d61902e072a0f5","versionType":"git"},{"version":"ce63cb62d794c98c7631c2296fa845f2a8d0a4a1","status":"affected","lessThan":"bbfe756dc3062c1e934f06e5ba39c239aa953b92","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/erofs/fileio.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.29","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.14.7","status":"unaffected","lessThanOrEqual":"6.14.*","versionType":"semver"},{"version":"6.15","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/erofs/fileio.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/61e0fc3312309867e5a3495329dad0286d2a5703"},{"url":"https://git.kernel.org/stable/c/c26076197df348c84cc23e5962d61902e072a0f5"},{"url":"https://git.kernel.org/stable/c/bbfe756dc3062c1e934f06e5ba39c239aa953b92"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:19:21.337Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.29"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.14.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.15"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}