{"cve":"CVE-2022-50534","nvd":{"published":"2025-10-07T16:15:37.530","modified":"2026-06-17T05:23:44.490","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm thin: Use last transaction's pmd->root 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   <IRQ>\n   dump_stack+0x9c/0xd3\n   panic+0x35d/0x6b9\n   watchdog_timer_fn.cold+0x16/0x25\n   __run_hrtimer+0xa2/0x2d0\n   </IRQ>\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->root = A, A->B->C   // One path in btree\n                pmd->root = X, X->Y->Z   // 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->root)\nThe pmd->root 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->root in __open_metadata(), so that dm thin\nwill use the last transaction's pmd->root if commit failed.\n\nFetch a reproducer in [Link].\n\nLinke: https://bugzilla.kernel.org/show_bug.cgi?id=216790","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/3db757ffdd87ed8d7118b2250236a496502a660f","https://git.kernel.org/stable/c/4b710e8481ade7c9200e94d3018e99dc42a0a0e8","https://git.kernel.org/stable/c/7991dbff6849f67e823b7cc0c15e5a90b0549b9f","https://git.kernel.org/stable/c/87d69b8824ca9b090f5a8ed47f758e8f6eecb871","https://git.kernel.org/stable/c/94f01ecc2aa0be992865acc80ebb6701f731f955"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:11:26.888974865+00:00"},"epss":{"cve":"CVE-2022-50534","score":0.00163,"percentile":0.05515,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}