CVE-2025-71126 in Linux
요약
\~에 의해 VulDB • 2026. 05. 28.
리눅스 커널에서 다음 취약점이 해결되었습니다:
mptcp: 재주입(reinjecting) 중 폴백(fallback) 시 데드락 방지
Jakub는 폴백 시점의 MPTCP 데드락을 보고했습니다:
WARNING: possible recursive locking detected 6.18.0-rc7-virtme #1 Not tainted -------------------------------------------- mptcp_connect/20858 is trying to acquire lock: ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_try_fallback+0xd8/0x280
but task is already holding lock: ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0
other info that might help us debug this: Possible unsafe locking scenario:
CPU0 ---- lock(&msk->fallback_lock); lock(&msk->fallback_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by mptcp_connect/20858: #0: ff1100001da18290 (sk_lock-AF_MPTCP){+.+.}-{0:0}, at: sock_lock+0x18/0x120
#1: ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0
#2: ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_try_fallback+0xd8/0x280
stack backtrace: CPU: 0 UID: 0 PID: 20858 Comm: mptcp_connect Not tainted 6.18.0-rc7-virtme #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x59/0x80 __lock_acquire+0x1238/0x20f0 lock_acquire+0x119/0x3a0 _raw_spin_lock+0x33/0x120 __mptcp_try_fallback+0xd8/0x280 __mptcp_retrans+0x352/0xaa0 mptcp_retransmit_handler+0x10/0x20 tcp_retransmit_timer+0x100/0x1100 tcp_write_timer+0x10/0x20 __run_hrtimer+0x100/0x3a0 hrtimer_interrupt+0x120/0x310 __sysvec_apic_timer_interrupt+0x59/0x100 sysvec_apic_timer_interrupt+0x4a/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 </TASK>
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