fkie_cve-2022-50534
Vulnerability from fkie_nvd
Published
2025-10-07 16:15
Modified
2025-10-08 19:38
Severity ?
Summary
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: <IRQ> dump_stack+0x9c/0xd3 panic+0x35d/0x6b9 watchdog_timer_fn.cold+0x16/0x25 __run_hrtimer+0xa2/0x2d0 </IRQ> 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
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3db757ffdd87ed8d7118b2250236a496502a660f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4b710e8481ade7c9200e94d3018e99dc42a0a0e8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7991dbff6849f67e823b7cc0c15e5a90b0549b9f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/87d69b8824ca9b090f5a8ed47f758e8f6eecb871
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/94f01ecc2aa0be992865acc80ebb6701f731f955
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a63ce4eca86fd207e3db07c00fb7ccf4adf1b230
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b35a22760aa5008d82533e59b0f0b5eb1b02d4e5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b91f481300e3a10eaf66b94fc39b740928762aaf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f758987ff0af3a4b5ee69e95cab6a5294e4367b0
Impacted products
Vendor Product Version


To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2022-50534",
  "lastModified": "2025-10-08T19:38:32.610",
  "metrics": {},
  "published": "2025-10-07T16:15:37.530",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3db757ffdd87ed8d7118b2250236a496502a660f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4b710e8481ade7c9200e94d3018e99dc42a0a0e8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7991dbff6849f67e823b7cc0c15e5a90b0549b9f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/87d69b8824ca9b090f5a8ed47f758e8f6eecb871"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/94f01ecc2aa0be992865acc80ebb6701f731f955"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a63ce4eca86fd207e3db07c00fb7ccf4adf1b230"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b35a22760aa5008d82533e59b0f0b5eb1b02d4e5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b91f481300e3a10eaf66b94fc39b740928762aaf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f758987ff0af3a4b5ee69e95cab6a5294e4367b0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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