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+<think>
+Okay, so I'm trying to help figure out why this system is having issues with workqueue lockups when using SSH over certain networks. From the logs provided, it seems like there's a problem where the workqueues are getting stuck, specifically on CPU 1. The error message mentions that the pool has been stuck for 30 seconds, which suggests some kind of deadlock or resource contention.
+
+Looking at the context, the user mentioned that this mostly happens when using SSH over what they call a "user" network connection. They gave examples like editing files in Vim via SSH and using the X clipboard, as well as SSHFS. It's interesting that it doesn't happen with "tap" connections but does with others, so maybe there's something about how different network interfaces handle certain types of traffic or protocols.
+
+First, I should understand what a workqueue lockup is. From my knowledge, workqueues in Linux are used by the kernel to manage tasks that need to be executed in the background. If a workqueue becomes stuck, it means that one of these tasks isn't completing, causing other tasks to wait indefinitely. This can lead to system hangs or freezes because the kernel's internal state gets blocked.
+
+Looking at the logs, there are several workqueues listed. The problematic one is under pool 2, which has flags=0x0, nice=0, and has been stuck for 30 seconds. The pending task here is "ata_sff_pio_task [libata]", but it's actually in flight on another queue, so that might not be the cause.
+
+Wait, no—the log shows that under workqueue events_freezable_power_, there's a task 4783:disk_events_workfn in-flight. That could be a disk-related issue. Maybe when SSH is active and data is being transferred, it's causing some I/O scheduler issues or the disk subsystem to get bogged down.
+
+Another angle is that using X over SSH with clipboard operations might involve more network traffic or specific protocol interactions. Perhaps there's some interaction between the SSH session handling and the kernel's workqueues when certain types of data are being transmitted.
+
+I also notice that different NICs were tested—virtio and e1000—but only "user" connections cause issues, not taps. Tap interfaces might have different priority or handling in the network stack, so maybe the problem is related to how packets are routed or handled on certain types of interfaces.
+
+Another thought: perhaps the kernel's scheduling for workqueues isn't getting CPU 1's attention properly when other processes are using it heavily. If SSH is a CPU-intensive operation (like encrypting data), it might starve the workqueue tasks, causing them to wait too long and trigger the lockup detection.
+
+I should also consider if there's any kind of resource exhaustion happening—like if some kernel resource isn't being freed up quickly enough when handling SSH traffic. Maybe certain network-related tasks are leaving some structures in an inconsistent state, preventing workqueues from completing.
+
+Looking at possible solutions: maybe adjusting the nice level or priority of certain workqueues could help them get scheduled more promptly. Alternatively, there might be a bug in how the kernel handles specific types of network connections that's causing these deadlocks. Upgrading the kernel or applying patches related to workqueue scheduling and network drivers might resolve it.
+
+I should also check if any recent changes to SSH configurations or system updates could have introduced this behavior. Sometimes, driver updates or kernel changes can introduce regressions in certain environments.
+
+In summary, the issue seems tied to SSH over "user" networks causing kernel workqueues to hang, particularly on CPU 1. Potential causes include resource contention, scheduling issues, or specific handling of network interfaces that lead to deadlocks in workqueue tasks. Testing with different kernel versions, adjusting priorities, and checking for any related bugs might help identify the root cause.
+</think>
+
+The issue at hand involves a Linux system experiencing workqueue lockups when using SSH over certain types of network connections, particularly "user" networks. Here's a structured analysis and proposed solution:
+
+### Problem Analysis:
+1. **Workqueue Lockup**: The logs indicate that a workqueue becomes stuck on CPU 1, leading to system hangs. Workqueues are kernel mechanisms for managing background tasks; their deadlock suggests resource contention or scheduling issues.
+
+2. **Network Type Sensitivity**: The problem occurs with "user" network connections (e.g., SSH, SSHFS) but not with "tap" interfaces. This implies that the issue is related to how specific network types are handled by the kernel's networking stack.
+
+3. **User Scenarios**: The problem arises during activities like editing files via Vim over SSH and using X clipboard operations. These activities involve significant network traffic and might interact differently with the kernel, possibly causing I/O scheduler issues or resource exhaustion.
+
+### Potential Causes:
+- **Resource Contention**: High CPU usage by SSH sessions (due to encryption) may starve workqueue tasks, preventing them from completing in time.
+- **Kernel Scheduling Issues**: The way workqueues are scheduled on CPU 1 might be affected by other processes, especially under heavy network load.
+- **Network Handling Differences**: "User" connections might involve different priority or handling compared to "tap" interfaces, leading to specific interactions that cause deadlocks.
+
+### Proposed Solutions:
+1. **Kernel and Driver Updates**: Check for updates or patches related to workqueue scheduling and network drivers. A newer kernel version might have resolved the issue.
+
+2. **Adjust Workqueue Priorities**: Modify the nice level of certain workqueues to ensure they get sufficient CPU time, preventing starvation under high load.
+
+3. **Inspect System Resources**: Monitor resource usage during periods when the lockup occurs to identify any patterns or resource exhaustion that could be contributing to the problem.
+
+4. **Review SSH Configuration**: Look for recent changes in SSH settings or system updates that might have introduced this behavior. Reverting to a previous configuration or applying known fixes could help.
+
+### Conclusion:
+The workqueue lockups are likely due to interactions between SSH traffic and kernel scheduling, exacerbated by specific network interface handling. Addressing the issue may involve updating kernel components, adjusting task priorities, or modifying how certain network types are managed. Further investigation into recent system changes and resource usage during these events will be crucial for pinpointing the exact cause and implementing a resolution.
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