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How the mentioned CVE works:
The vulnerability exists in the Intel IDPF network driver within the Linux kernel. When the VIRTCHNL2_CAP_MACFILTER capability is enabled, a specific code path is triggered during network interface initialization. The `idpf_set_rx_mode` function is called, which eventually leads to idpf_ctlq_clean_sq. This function incorrectly uses a mutex lock (cq_lock) for synchronization. The locking issue arises because the call chain starts from `rtnl_newlink` which holds the RTNL mutex and `dev->addr_list_lock` with bottom-half (BH) processing disabled. Attempting to acquire a sleeping mutex (cq_lock) within this atomic context triggers a kernel warning, as a mutex can sleep and cannot be used when preemption is disabled or in atomic sections, potentially leading to a deadlock or system instability.
DailyCVE Form:
Platform: Linux Kernel
Version: idpf driver
Vulnerability: Race Condition
Severity: Medium
Date: 2025-07-25
Prediction: 2025-08-15
What Undercode Say:
dmesg | grep "BUG: sleeping function" cat /proc/version lsmod | grep idpf
// Code snippet showing the problematic mutex lock
mutex_lock(&cq->cq_lock);
idpf_ctlq_clean_sq(..., struct idpf_ctlq_info cq) {
...
}
// The fix replaces it with a spinlock:
spin_lock(&cq->cq_lock);
How Exploit:
A local user could potentially trigger this condition by forcing specific network interface states, causing the kernel to attempt to acquire the mutex in an invalid context. This could lead to a kernel warning or a deadlock, resulting in a denial-of-service (DoS) condition for the specific network interface or a system crash if the deadlock affects core kernel operations.
Protection from this CVE:
Apply the kernel patch that converts the control queue mutex (cq_lock) to a spinlock and ensures contiguous DMA memory allocation. Update to a Linux kernel version containing the commit that resolves this issue. For users unable to patch immediately, a potential workaround is to disable the VIRTCHNL2_CAP_MACFILTER capability for the idpf driver if possible, though this may reduce functionality.
Impact:
Denial-of-Service (DoS) through system instability or kernel crash. The vulnerability disrupts normal network operations and can halt system processes, requiring a reboot to restore functionality.
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Sources:
Reported By: nvd.nist.gov
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