{"id":"CVE-2024-47736","summary":"erofs: handle overlapped pclusters out of crafted images properly","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nerofs: handle overlapped pclusters out of crafted images properly\n\nsyzbot reported a task hang issue due to a deadlock case where it is\nwaiting for the folio lock of a cached folio that will be used for\ncache I/Os.\n\nAfter looking into the crafted fuzzed image, I found it's formed with\nseveral overlapped big pclusters as below:\n\n Ext:   logical offset   |  length :     physical offset    |  length\n   0:        0..   16384 |   16384 :     151552..    167936 |   16384\n   1:    16384..   32768 |   16384 :     155648..    172032 |   16384\n   2:    32768..   49152 |   16384 :  537223168.. 537239552 |   16384\n...\n\nHere, extent 0/1 are physically overlapped although it's entirely\n_impossible_ for normal filesystem images generated by mkfs.\n\nFirst, managed folios containing compressed data will be marked as\nup-to-date and then unlocked immediately (unlike in-place folios) when\ncompressed I/Os are complete.  If physical blocks are not submitted in\nthe incremental order, there should be separate BIOs to avoid dependency\nissues.  However, the current code mis-arranges z_erofs_fill_bio_vec()\nand BIO submission which causes unexpected BIO waits.\n\nSecond, managed folios will be connected to their own pclusters for\nefficient inter-queries.  However, this is somewhat hard to implement\neasily if overlapped big pclusters exist.  Again, these only appear in\nfuzzed images so let's simply fall back to temporary short-lived pages\nfor correctness.\n\nAdditionally, it justifies that referenced managed folios cannot be\ntruncated for now and reverts part of commit 2080ca1ed3e4 (\"erofs: tidy\nup `struct z_erofs_bvec`\") for simplicity although it shouldn't be any\ndifference.","modified":"2026-04-02T12:20:28.297686Z","published":"2024-10-21T12:14:06.530Z","related":["USN-7276-1","USN-7277-1","openSUSE-SU-2024:14500-1","openSUSE-SU-2025:14705-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/47xxx/CVE-2024-47736.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1bf7e414cac303c9aec1be67872e19be8b64980c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9cfa199bcbbbba31cbf97b2786f44f4464f3f29a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b9b30af0e86ffb485301ecd83b9129c9dfb7ebf8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/47xxx/CVE-2024-47736.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-47736"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8e6c8fa9f2e95c88a642521a5da19a8e31748846"},{"fixed":"1bf7e414cac303c9aec1be67872e19be8b64980c"},{"fixed":"b9b30af0e86ffb485301ecd83b9129c9dfb7ebf8"},{"fixed":"9cfa199bcbbbba31cbf97b2786f44f4464f3f29a"},{"fixed":"9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-47736.json"}}],"schema_version":"1.7.5"}