CVE-2025-71132
Publiée le 2026-01-14 · Dernière modification le 2026-10-19
Les systèmes Linux utilisant le pilote réseau `smc91x` et le patch temps réel `PREEMPT_RT` sont concernés. Un attaquant distant et non authentifié peut provoquer un plantage du noyau (déni de service) en envoyant un trafic réseau spécifique, car le pilote gère incorrectement le verrouillage des interruptions. Cette attaque est relativement facile à exécuter car elle ne nécessite aucune interaction de l'utilisateur ni d'accès préalable au système.
DÉTAIL DU VECTEUR CVSS
RÉFÉRENCES
Description officielle du NVD (en anglais)
In the Linux kernel, the following vulnerability has been resolved: smc91x: fix broken irq-context in PREEMPT_RT When smc91x.c is built with PREEMPT_RT, the following splat occurs in FVP_RevC: [ 13.055000] smc91x LNRO0003:00 eth0: link up, 10Mbps, half-duplex, lpa 0x0000 [ 13.062137] BUG: workqueue leaked atomic, lock or RCU: kworker/2:1[106] [ 13.062137] preempt=0x00000000 lock=0->0 RCU=0->1 workfn=mld_ifc_work [ 13.062266] C ** replaying previous printk message ** [ 13.062266] CPU: 2 UID: 0 PID: 106 Comm: kworker/2:1 Not tainted 6.18.0-dirty #179 PREEMPT_{RT,(full)} [ 13.062353] Hardware name: , BIOS [ 13.062382] Workqueue: mld mld_ifc_work [ 13.062469] Call trace: [ 13.062494] show_stack+0x24/0x40 (C) [ 13.062602] __dump_stack+0x28/0x48 [ 13.062710] dump_stack_lvl+0x7c/0xb0 [ 13.062818] dump_stack+0x18/0x34 [ 13.062926] process_scheduled_works+0x294/0x450 [ 13.063043] worker_thread+0x260/0x3d8 [ 13.063124] kthread+0x1c4/0x228 [ 13.063235] ret_from_fork+0x10/0x20 This happens because smc_special_trylock() disables IRQs even on PREEMPT_RT, but smc_special_unlock() does not restore IRQs on PREEMPT_RT. The reason is that smc_special_unlock() calls spin_unlock_irqrestore(), and rcu_read_unlock_bh() in __dev_queue_xmit() cannot invoke rcu_read_unlock() through __local_bh_enable_ip() when current->softirq_disable_cnt becomes zero. To address this issue, replace smc_special_trylock() with spin_trylock_irqsave().