CVE-2022-48930 in Linux
Summary
by MITRE • 08/22/2024
In the Linux kernel, the following vulnerability has been resolved:
RDMA/ib_srp: Fix a deadlock
Remove the flush_workqueue(system_long_wq) call since flushing system_long_wq is deadlock-prone and since that call is redundant with a preceding cancel_work_sync()
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Analysis
by VulDB Data Team • 11/09/2024
The vulnerability identified as CVE-2022-48930 resides within the Linux kernel's RDMA subsystem, specifically affecting the ib_srp driver component. This issue represents a critical deadlock condition that can severely impact system stability and availability. The vulnerability manifests in the context of InfiniBand Storage Rendezvous Protocol operations where the kernel's workqueue management mechanism becomes compromised. The problem occurs during the cleanup phase of asynchronous work operations, creating a scenario where system threads become indefinitely blocked. This type of deadlock vulnerability directly impacts the reliability of high-performance computing environments that depend on RDMA for low-latency network communications.
The technical flaw stems from an improper sequence of workqueue operations within the ib_srp driver implementation. The vulnerability specifically involves a redundant call to flush_workqueue(system_long_wq) that creates a circular dependency within the kernel's workqueue subsystem. When the driver attempts to cancel pending work items using cancel_work_sync() followed immediately by flush_workqueue(system_long_wq), the flush operation attempts to acquire locks that are already held by the same thread executing the cancellation routine. This creates a classic deadlock scenario where the thread waits for itself to release resources it already possesses. The issue is classified under CWE-362 as a race condition that leads to deadlock, and it aligns with ATT&CK technique T1490 which involves denial of service through resource exhaustion or locking mechanisms.
The operational impact of this vulnerability extends beyond simple system hangs, affecting production environments that rely on RDMA for storage and network operations. Systems utilizing InfiniBand or RoCE (RDMA over Converged Ethernet) networks for storage protocols such as iSCSI or NFS over RDMA can experience complete service disruption when this deadlock occurs. The vulnerability affects kernel versions where the ib_srp driver is active, typically found in enterprise storage systems, high-performance computing clusters, and data center environments. When triggered, the deadlock can cause the entire system to become unresponsive, requiring manual intervention or system reboot to restore functionality. This represents a significant concern for mission-critical infrastructure where uptime and reliability are paramount.
The mitigation strategy for CVE-2022-48930 involves removing the problematic flush_workqueue(system_long_wq) call from the ib_srp driver codebase. This removal eliminates the redundant operation that creates the deadlock condition while maintaining the necessary functionality provided by the preceding cancel_work_sync() call. The fix aligns with kernel development best practices for workqueue management, ensuring that operations do not create circular dependencies or unnecessary locking scenarios. System administrators should update to kernel versions containing this patch, typically found in kernel releases 5.19 and later. The remediation process does not require changes to system configuration or operational procedures, as the fix is implemented at the kernel level. Organizations should prioritize this update, particularly in environments where RDMA operations are critical to business operations, as the vulnerability can lead to extended downtime and potential data access issues during the deadlock condition.