ghsa-84fr-rw9r-j8p4
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
dm thin: Use last transaction's pmd->root 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: dump_stack+0x9c/0xd3 panic+0x35d/0x6b9 watchdog_timer_fn.cold+0x16/0x25 __run_hrtimer+0xa2/0x2d0 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->root = A, A->B->C // One path in btree pmd->root = X, X->Y->Z // Copy-up Transaction 2: X,Z is updated on disk, Y write failed. // Commit failed, dm thin becomes read-only. process_bio_read_only dm_thin_find_block __find_block dm_btree_lookup(pmd->root) The pmd->root 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->root in __open_metadata(), so that dm thin will use the last transaction's pmd->root if commit failed.
Fetch a reproducer in [Link].
Linke: https://bugzilla.kernel.org/show_bug.cgi?id=216790
{
"affected": [],
"aliases": [
"CVE-2022-50534"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-07T16:15:37Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm thin: Use last transaction\u0027s 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\u0027s pmd-\u003eroot if commit failed.\n\nFetch a reproducer in [Link].\n\nLinke: https://bugzilla.kernel.org/show_bug.cgi?id=216790",
"id": "GHSA-84fr-rw9r-j8p4",
"modified": "2025-10-07T18:31:08Z",
"published": "2025-10-07T18:31:08Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50534"
},
{
"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"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.