CVE-2022-50116 | tty: n_gsm: fix deadlock and link starvation in outgoing data path

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---

Published: 2025-06-18 Last update: 2026-06-01 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2022-50116 is rated Low Risk (27.6/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2022-50116

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-02 0.02% 0.05% +0.03%
2 2025-06-18 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-50116

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2022-50116

GitHub Security Advisory for CVE-2022-50116

GHSA-gf27-p5cc-4mq4 · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: tty: n_gsm: fix deadlock and...

OS Trackers for CVE-2022-50116

vendor priority summary link
debian not yet assigned CVE-2022-50116 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2022-50116
redhat medium — https://access.redhat.com/security/cve/CVE-2022-50116
suse medium — https://www.suse.com/security/cve/CVE-2022-50116/
ubuntu medium CVE-2022-50116 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, ignored 151, released 92, not-affected 89, needed 74. https://ubuntu.com/security/CVE-2022-50116

Affected software / configurations for CVE-2022-50116

Vendor Product Version Raw CPE
linux linux_kernel >= 2.6.35, < 5.18.18 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.19, < 5.19.2 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

References for CVE-2022-50116

cvelogic Threat Intelligence