CVE-2022-50116 (GCVE-0-2022-50116)

Vulnerability from cvelistv5 – Published: 2025-06-18 11:02 – Updated: 2025-06-18 11:02
VLAI?
Title
tty: n_gsm: fix deadlock and link starvation in outgoing data path
Summary
In the Linux kernel, the following vulnerability has been resolved: tty: n_gsm: fix deadlock and link starvation in outgoing data path The current implementation queues up new control and user packets as needed and processes this queue down to the ldisc in the same code path. That means that the upper and the lower layer are hard coupled in the code. Due to this deadlocks can happen as seen below while transmitting data, especially during ldisc congestion. Furthermore, the data channels starve the control channel on high transmission load on the ldisc. Introduce an additional control channel data queue to prevent timeouts and link hangups during ldisc congestion. This is being processed before the user channel data queue in gsm_data_kick(), i.e. with the highest priority. Put the queue to ldisc data path into a workqueue and trigger it whenever new data has been put into the transmission queue. Change gsm_dlci_data_sweep() accordingly to fill up the transmission queue until TX_THRESH_HI. This solves the locking issue, keeps latency low and provides good performance on high data load. Note that now all packets from a DLCI are removed from the internal queue if the associated DLCI was closed. This ensures that no data is sent by the introduced write task to an already closed DLCI. BUG: spinlock recursion on CPU#0, test_v24_loop/124 lock: serial8250_ports+0x3a8/0x7500, .magic: dead4ead, .owner: test_v24_loop/124, .owner_cpu: 0 CPU: 0 PID: 124 Comm: test_v24_loop Tainted: G O 5.18.0-rc2 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x34/0x44 do_raw_spin_lock+0x76/0xa0 _raw_spin_lock_irqsave+0x72/0x80 uart_write_room+0x3b/0xc0 gsm_data_kick+0x14b/0x240 [n_gsm] gsmld_write_wakeup+0x35/0x70 [n_gsm] tty_wakeup+0x53/0x60 tty_port_default_wakeup+0x1b/0x30 serial8250_tx_chars+0x12f/0x220 serial8250_handle_irq.part.0+0xfe/0x150 serial8250_default_handle_irq+0x48/0x80 serial8250_interrupt+0x56/0xa0 __handle_irq_event_percpu+0x78/0x1f0 handle_irq_event+0x34/0x70 handle_fasteoi_irq+0x90/0x1e0 __common_interrupt+0x69/0x100 common_interrupt+0x48/0xc0 asm_common_interrupt+0x1e/0x40 RIP: 0010:__do_softirq+0x83/0x34e Code: 2a 0a ff 0f b7 ed c7 44 24 10 0a 00 00 00 48 c7 c7 51 2a 64 82 e8 2d e2 d5 ff 65 66 c7 05 83 af 1e 7e 00 00 fb b8 ff ff ff ff <49> c7 c2 40 61 80 82 0f bc c5 41 89 c4 41 83 c4 01 0f 84 e6 00 00 RSP: 0018:ffffc90000003f98 EFLAGS: 00000286 RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff82642a51 RDI: ffffffff825bb5e7 RBP: 0000000000000200 R08: 00000008de3271a8 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000030 R14: 0000000000000000 R15: 0000000000000000 ? __do_softirq+0x73/0x34e irq_exit_rcu+0xb5/0x100 common_interrupt+0xa4/0xc0 </IRQ> <TASK> asm_common_interrupt+0x1e/0x40 RIP: 0010:_raw_spin_unlock_irqrestore+0x2e/0x50 Code: 00 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 85 28 36 ff 48 89 ef e8 cd 58 36 ff 80 e7 02 74 01 fb bf 01 00 00 00 <e8> 3d 97 33 ff 65 8b 05 96 23 2b 7e 85 c0 74 03 5b 5d c3 0f 1f 44 RSP: 0018:ffffc9000020fd08 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000 RDX: 0000000000000004 RSI: ffffffff8257fd74 RDI: 0000000000000001 RBP: ffff8880057de3a0 R08: 00000008de233000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000100 R14: 0000000000000202 R15: ffff8880057df0b8 ? _raw_spin_unlock_irqrestore+0x23/0x50 gsmtty_write+0x65/0x80 [n_gsm] n_tty_write+0x33f/0x530 ? swake_up_all+0xe0/0xe0 file_tty_write.constprop.0+0x1b1/0x320 ? n_tty_flush_buffer+0xb0/0xb0 new_sync_write+0x10c/0x190 vfs_write+0x282/0x310 ksys_write+0x68/0xe0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3e5e35c15c Code: 8b 7c 24 08 89 c5 e8 c5 ff ff ff 89 ef 89 44 24 ---truncated---
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: e1eaea46bb4020b38a141b84f88565d4603f8dd0 , < c165698c9919b000bdbe73859d3bb7b33bdb9223 (git)
Affected: e1eaea46bb4020b38a141b84f88565d4603f8dd0 , < 7962a4b900099cf90e02859bb297f2c618d8d940 (git)
Affected: e1eaea46bb4020b38a141b84f88565d4603f8dd0 , < 0af021678d5d30c31f5a6b631f404ead3575212a (git)
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    Linux Linux Affected: 2.6.35
Unaffected: 0 , < 2.6.35 (semver)
Unaffected: 5.18.18 , ≤ 5.18.* (semver)
Unaffected: 5.19.2 , ≤ 5.19.* (semver)
Unaffected: 6.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/tty/n_gsm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c165698c9919b000bdbe73859d3bb7b33bdb9223",
              "status": "affected",
              "version": "e1eaea46bb4020b38a141b84f88565d4603f8dd0",
              "versionType": "git"
            },
            {
              "lessThan": "7962a4b900099cf90e02859bb297f2c618d8d940",
              "status": "affected",
              "version": "e1eaea46bb4020b38a141b84f88565d4603f8dd0",
              "versionType": "git"
            },
            {
              "lessThan": "0af021678d5d30c31f5a6b631f404ead3575212a",
              "status": "affected",
              "version": "e1eaea46bb4020b38a141b84f88565d4603f8dd0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/tty/n_gsm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.35"
            },
            {
              "lessThan": "2.6.35",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.18.*",
              "status": "unaffected",
              "version": "5.18.18",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.19.*",
              "status": "unaffected",
              "version": "5.19.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.18.18",
                  "versionStartIncluding": "2.6.35",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.19.2",
                  "versionStartIncluding": "2.6.35",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0",
                  "versionStartIncluding": "2.6.35",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: n_gsm: fix deadlock and link starvation in outgoing data path\n\nThe current implementation queues up new control and user packets as needed\nand processes this queue down to the ldisc in the same code path.\nThat means that the upper and the lower layer are hard coupled in the code.\nDue to this deadlocks can happen as seen below while transmitting data,\nespecially during ldisc congestion. Furthermore, the data channels starve\nthe control channel on high transmission load on the ldisc.\n\nIntroduce an additional control channel data queue to prevent timeouts and\nlink hangups during ldisc congestion. This is being processed before the\nuser channel data queue in gsm_data_kick(), i.e. with the highest priority.\nPut the queue to ldisc data path into a workqueue and trigger it whenever\nnew data has been put into the transmission queue. Change\ngsm_dlci_data_sweep() accordingly to fill up the transmission queue until\nTX_THRESH_HI. This solves the locking issue, keeps latency low and provides\ngood performance on high data load.\nNote that now all packets from a DLCI are removed from the internal queue\nif the associated DLCI was closed. This ensures that no data is sent by the\nintroduced write task to an already closed DLCI.\n\nBUG: spinlock recursion on CPU#0, test_v24_loop/124\n lock: serial8250_ports+0x3a8/0x7500, .magic: dead4ead, .owner: test_v24_loop/124, .owner_cpu: 0\nCPU: 0 PID: 124 Comm: test_v24_loop Tainted: G           O      5.18.0-rc2 #3\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\nCall Trace:\n \u003cIRQ\u003e\n dump_stack_lvl+0x34/0x44\n do_raw_spin_lock+0x76/0xa0\n _raw_spin_lock_irqsave+0x72/0x80\n uart_write_room+0x3b/0xc0\n gsm_data_kick+0x14b/0x240 [n_gsm]\n gsmld_write_wakeup+0x35/0x70 [n_gsm]\n tty_wakeup+0x53/0x60\n tty_port_default_wakeup+0x1b/0x30\n serial8250_tx_chars+0x12f/0x220\n serial8250_handle_irq.part.0+0xfe/0x150\n serial8250_default_handle_irq+0x48/0x80\n serial8250_interrupt+0x56/0xa0\n __handle_irq_event_percpu+0x78/0x1f0\n handle_irq_event+0x34/0x70\n handle_fasteoi_irq+0x90/0x1e0\n __common_interrupt+0x69/0x100\n common_interrupt+0x48/0xc0\n asm_common_interrupt+0x1e/0x40\nRIP: 0010:__do_softirq+0x83/0x34e\nCode: 2a 0a ff 0f b7 ed c7 44 24 10 0a 00 00 00 48 c7 c7 51 2a 64 82 e8 2d\ne2 d5 ff 65 66 c7 05 83 af 1e 7e 00 00 fb b8 ff ff ff ff \u003c49\u003e c7 c2 40 61\n80 82 0f bc c5 41 89 c4 41 83 c4 01 0f 84 e6 00 00\nRSP: 0018:ffffc90000003f98 EFLAGS: 00000286\nRAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000\nRDX: 0000000000000000 RSI: ffffffff82642a51 RDI: ffffffff825bb5e7\nRBP: 0000000000000200 R08: 00000008de3271a8 R09: 0000000000000000\nR10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000\nR13: 0000000000000030 R14: 0000000000000000 R15: 0000000000000000\n ? __do_softirq+0x73/0x34e\n irq_exit_rcu+0xb5/0x100\n common_interrupt+0xa4/0xc0\n \u003c/IRQ\u003e\n \u003cTASK\u003e\n asm_common_interrupt+0x1e/0x40\nRIP: 0010:_raw_spin_unlock_irqrestore+0x2e/0x50\nCode: 00 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 85 28 36 ff\n48 89 ef e8 cd 58 36 ff 80 e7 02 74 01 fb bf 01 00 00 00 \u003ce8\u003e 3d 97 33 ff\n65 8b 05 96 23 2b 7e 85 c0 74 03 5b 5d c3 0f 1f 44\nRSP: 0018:ffffc9000020fd08 EFLAGS: 00000202\nRAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000\nRDX: 0000000000000004 RSI: ffffffff8257fd74 RDI: 0000000000000001\nRBP: ffff8880057de3a0 R08: 00000008de233000 R09: 0000000000000000\nR10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000\nR13: 0000000000000100 R14: 0000000000000202 R15: ffff8880057df0b8\n ? _raw_spin_unlock_irqrestore+0x23/0x50\n gsmtty_write+0x65/0x80 [n_gsm]\n n_tty_write+0x33f/0x530\n ? swake_up_all+0xe0/0xe0\n file_tty_write.constprop.0+0x1b1/0x320\n ? n_tty_flush_buffer+0xb0/0xb0\n new_sync_write+0x10c/0x190\n vfs_write+0x282/0x310\n ksys_write+0x68/0xe0\n do_syscall_64+0x3b/0x90\n entry_SYSCALL_64_after_hwframe+0x44/0xae\nRIP: 0033:0x7f3e5e35c15c\nCode: 8b 7c 24 08 89 c5 e8 c5 ff ff ff 89 ef 89 44 24\n---truncated---"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-06-18T11:02:47.361Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c165698c9919b000bdbe73859d3bb7b33bdb9223"
        },
        {
          "url": "https://git.kernel.org/stable/c/7962a4b900099cf90e02859bb297f2c618d8d940"
        },
        {
          "url": "https://git.kernel.org/stable/c/0af021678d5d30c31f5a6b631f404ead3575212a"
        }
      ],
      "title": "tty: n_gsm: fix deadlock and link starvation in outgoing data path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-50116",
    "datePublished": "2025-06-18T11:02:47.361Z",
    "dateReserved": "2025-06-18T10:57:27.415Z",
    "dateUpdated": "2025-06-18T11:02:47.361Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.