{"id":"DEBIAN-CVE-2022-50534","details":"In the Linux kernel, the following vulnerability has been resolved:  dm thin: Use last transaction's pmd-\u003eroot when commit failed  Recently we found a softlock up problem in dm thin pool btree lookup code due to corrupted metadata:   Kernel panic - not syncing: softlockup: hung tasks  CPU: 7 PID: 2669225 Comm: kworker/u16:3  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)  Workqueue: dm-thin do_worker [dm_thin_pool]  Call Trace:    \u003cIRQ\u003e    dump_stack+0x9c/0xd3    panic+0x35d/0x6b9    watchdog_timer_fn.cold+0x16/0x25    __run_hrtimer+0xa2/0x2d0    \u003c/IRQ\u003e    RIP: 0010:__relink_lru+0x102/0x220 [dm_bufio]    __bufio_new+0x11f/0x4f0 [dm_bufio]    new_read+0xa3/0x1e0 [dm_bufio]    dm_bm_read_lock+0x33/0xd0 [dm_persistent_data]    ro_step+0x63/0x100 [dm_persistent_data]    btree_lookup_raw.constprop.0+0x44/0x220 [dm_persistent_data]    dm_btree_lookup+0x16f/0x210 [dm_persistent_data]    dm_thin_find_block+0x12c/0x210 [dm_thin_pool]    __process_bio_read_only+0xc5/0x400 [dm_thin_pool]    process_thin_deferred_bios+0x1a4/0x4a0 [dm_thin_pool]    process_one_work+0x3c5/0x730  Following process may generate a broken btree mixed with fresh and stale btree nodes, which could get dm thin trapped in an infinite loop while looking up data block:  Transaction 1: pmd-\u003eroot = A, A-\u003eB-\u003eC   // One path in btree                 pmd-\u003eroot = X, X-\u003eY-\u003eZ   // Copy-up  Transaction 2: X,Z is updated on disk, Y write failed.                 // Commit failed, dm thin becomes read-only.                 process_bio_read_only \t\t dm_thin_find_block \t\t  __find_block \t\t   dm_btree_lookup(pmd-\u003eroot) The pmd-\u003eroot points to a broken btree, Y may contain stale node pointing to any block, for example X, which gets dm thin trapped into a dead loop while looking up Z.  Fix this by setting pmd-\u003eroot in __open_metadata(), so that dm thin will use the last transaction's pmd-\u003eroot if commit failed.  Fetch a reproducer in [Link].  Linke: https://bugzilla.kernel.org/show_bug.cgi?id=216790","modified":"2026-09-01T16:05:35.725340437Z","published":"2025-10-07T16:15:37.530Z","upstream":["CVE-2022-50534"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2022-50534"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.4-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-50534.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.4-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-50534.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.4-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-50534.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}