CVE-2025-71132
smc91x: fix broken irq-context in PREEMPT_RT
Description
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().
INFO
Published Date :
Jan. 14, 2026, 3:16 p.m.
Last Modified :
Jan. 14, 2026, 4:25 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2025-71132
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Replace smc_special_trylock() with spin_trylock_irqsave().
- Ensure smc_special_unlock() restores IRQs correctly on PREEMPT_RT.
- Update kernel to include the fix.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-71132.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-71132 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-71132
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-71132 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-71132 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jan. 14, 2026
Action Type Old Value New Value Added Description 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(). Added Reference https://git.kernel.org/stable/c/36561b86cb2501647662cfaf91286dd6973804a6 Added Reference https://git.kernel.org/stable/c/6402078bd9d1ed46e79465e1faaa42e3458f8a33 Added Reference https://git.kernel.org/stable/c/9d222141b00156509d67d80c771fbefa92c43ace Added Reference https://git.kernel.org/stable/c/b6018d5c1a8f09d5efe4d6961d7ee45fdf3a7ce3 Added Reference https://git.kernel.org/stable/c/ef277ae121b3249c99994652210a326b52d527b0