{"id":"CVE-2022-50534","summary":"dm thin: Use last transaction's pmd-\u003eroot when commit failed","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm thin: Use last transaction's pmd-\u003eroot when commit failed\n\nRecently we found a softlock up problem in dm thin pool btree lookup\ncode due to corrupted metadata:\n\n Kernel panic - not syncing: softlockup: hung tasks\n CPU: 7 PID: 2669225 Comm: kworker/u16:3\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)\n Workqueue: dm-thin do_worker [dm_thin_pool]\n Call Trace:\n   \u003cIRQ\u003e\n   dump_stack+0x9c/0xd3\n   panic+0x35d/0x6b9\n   watchdog_timer_fn.cold+0x16/0x25\n   __run_hrtimer+0xa2/0x2d0\n   \u003c/IRQ\u003e\n   RIP: 0010:__relink_lru+0x102/0x220 [dm_bufio]\n   __bufio_new+0x11f/0x4f0 [dm_bufio]\n   new_read+0xa3/0x1e0 [dm_bufio]\n   dm_bm_read_lock+0x33/0xd0 [dm_persistent_data]\n   ro_step+0x63/0x100 [dm_persistent_data]\n   btree_lookup_raw.constprop.0+0x44/0x220 [dm_persistent_data]\n   dm_btree_lookup+0x16f/0x210 [dm_persistent_data]\n   dm_thin_find_block+0x12c/0x210 [dm_thin_pool]\n   __process_bio_read_only+0xc5/0x400 [dm_thin_pool]\n   process_thin_deferred_bios+0x1a4/0x4a0 [dm_thin_pool]\n   process_one_work+0x3c5/0x730\n\nFollowing process may generate a broken btree mixed with fresh and\nstale btree nodes, which could get dm thin trapped in an infinite loop\nwhile looking up data block:\n Transaction 1: pmd-\u003eroot = A, A-\u003eB-\u003eC   // One path in btree\n                pmd-\u003eroot = X, X-\u003eY-\u003eZ   // Copy-up\n Transaction 2: X,Z is updated on disk, Y write failed.\n                // Commit failed, dm thin becomes read-only.\n                process_bio_read_only\n\t\t dm_thin_find_block\n\t\t  __find_block\n\t\t   dm_btree_lookup(pmd-\u003eroot)\nThe pmd-\u003eroot points to a broken btree, Y may contain stale node\npointing to any block, for example X, which gets dm thin trapped into\na dead loop while looking up Z.\n\nFix this by setting pmd-\u003eroot in __open_metadata(), so that dm thin\nwill use the last transaction's pmd-\u003eroot if commit failed.\n\nFetch a reproducer in [Link].\n\nLinke: https://bugzilla.kernel.org/show_bug.cgi?id=216790","modified":"2026-04-11T12:44:57.606015Z","published":"2025-10-07T15:19:23.958Z","related":["SUSE-SU-2025:4111-1","SUSE-SU-2025:4135-1","SUSE-SU-2025:4139-1","SUSE-SU-2025:4149-1","SUSE-SU-2025:4188-1","SUSE-SU-2025:4189-1","SUSE-SU-2025:4320-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50534.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3db757ffdd87ed8d7118b2250236a496502a660f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4b710e8481ade7c9200e94d3018e99dc42a0a0e8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7991dbff6849f67e823b7cc0c15e5a90b0549b9f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/87d69b8824ca9b090f5a8ed47f758e8f6eecb871"},{"type":"WEB","url":"https://git.kernel.org/stable/c/94f01ecc2aa0be992865acc80ebb6701f731f955"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a63ce4eca86fd207e3db07c00fb7ccf4adf1b230"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b35a22760aa5008d82533e59b0f0b5eb1b02d4e5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b91f481300e3a10eaf66b94fc39b740928762aaf"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f758987ff0af3a4b5ee69e95cab6a5294e4367b0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50534.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-50534"},{"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":"991d9fa02da0dd1f843dc011376965e0c8c6c9b5"},{"fixed":"b35a22760aa5008d82533e59b0f0b5eb1b02d4e5"},{"fixed":"87d69b8824ca9b090f5a8ed47f758e8f6eecb871"},{"fixed":"3db757ffdd87ed8d7118b2250236a496502a660f"},{"fixed":"f758987ff0af3a4b5ee69e95cab6a5294e4367b0"},{"fixed":"94f01ecc2aa0be992865acc80ebb6701f731f955"},{"fixed":"4b710e8481ade7c9200e94d3018e99dc42a0a0e8"},{"fixed":"a63ce4eca86fd207e3db07c00fb7ccf4adf1b230"},{"fixed":"b91f481300e3a10eaf66b94fc39b740928762aaf"},{"fixed":"7991dbff6849f67e823b7cc0c15e5a90b0549b9f"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-50534.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.2.0"},{"fixed":"4.9.337"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.10.0"},{"fixed":"4.14.303"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.15.0"},{"fixed":"4.19.270"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.229"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.163"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.87"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.0.18"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"6.1.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-50534.json"}}],"schema_version":"1.7.5"}