CVE-2023-53556 in Linux
Сводка
по VulDB • 08.08.2026
Based on the kernel stack trace provided, here is an analysis of the issue and recommended troubleshooting steps.
### **Summary** The system experienced a **kernel panic or hang** while attempting to configure SR-IOV (Single Root I/O Virtualization) virtual functions for an Intel `i40e` network adapter. The crash occurred in the function `i40e_pci_sriov_configure`, which is called when writing to `/sys/class/net/<iface>/device/sriov_numvfs`.
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### **Key Details from Stack Trace** 1. **Driver**: `i40e` (Intel XL710/X710/XXV710 Ethernet driver). 2. **Function**: `i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e]`.
3. **Trigger**: Writing to the sysfs attribute `sriov_numvfs` (via `kernfs_fop_write`). 4. **Context**: The crash happened during a syscall (`do_syscall_64`) from user space, likely via a script or tool like `ip link set dev eth0 sriov num_vfs X`.
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### **Common Causes** 1. **Driver Bug in SR-IOV Configuration**: Older versions of the `i40e` driver had known bugs related to race conditions or improper cleanup when enabling/disabling VFs, especially if: - The PF (Physical Function) was not fully initialized. - Existing VFs were still active during reconfiguration. - There was a conflict with other kernel modules (e.g., `ixgbe`, `vfio-pci`). 2. **Hardware/Firmware Issue**: Outdated NIC firmware may cause the driver to hang when programming SR-IOV registers. 3. **Resource Exhaustion or Lock Contention**: The stack shows `__mutex_lock_slowpath`, indicating a potential deadlock or long lock contention in the mutex protecting SR-IOV configuration.
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### **Troubleshooting Steps**
#### **1. Update Driver and Firmware** - **Driver**: Ensure you are using the latest stable version of the `i40e` driver from [Intel's Linux Network Drivers](https://downloadcenter.intel.com/product/80939/Ethernet-Connectivity-Products).
- Check current version: `modinfo i40e | grep version` - **Firmware**: Update the NIC firmware using Intel’s `ethtool --update-firmware` or the provided flash utility.
#### **2. Reproduce with Debugging** If possible, enable kernel debugging to get more context: ```bash # Enable dynamic debug for i40e driver echo 'file drivers/net/ethernet/intel/i40e/*.c +p' > /sys/kernel/debug/dynamic_debug/control
# Then retry the SR-IOV configuration echo 2 > /sys/class/net/<iface>/device/sriov_numvfs ``` Check `dmesg` for additional logs before the crash.
#### **3. Check for Known Bugs** Search Intel’s bug tracker or kernel mailing lists for: - `"i40e sriov configure hang"` - `"i40e mutex lock deadlock sriv_numvfs"`
Common fixes involve updating to a newer kernel version (≥ 5.10) where many `i40e` SR-IOV issues were resolved.
#### **4. Workaround: Disable/Enable VFs Carefully** If the crash is reproducible, try this sequence instead of directly setting `num_vfs`: ```bash # Step 1: Remove all existing VFs first (if any) echo 0 > /sys/class/net/<iface>/device/sriov_numvfs
# Wait a few seconds for cleanup sleep 2
# Step 2: Enable the desired number of VFs echo <N> > /sys/class/net/<iface>/device/sriov_numvfs ```
#### **5. Check Kernel Logs** Look for earlier warnings in `dmesg` that might indicate hardware errors or driver issues preceding the crash: ```bash dmesg | grep -i i40e dmesg | grep -i sriov ```
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### **Conclusion** This is likely a **driver-level bug** in the `i40e` module when handling SR-IOV configuration. The most effective solution is to: 1. Update the `i40e` driver and NIC firmware. 2. Upgrade the kernel if possible (newer kernels have better SR-IOV stability). 3. If updating is not an option
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