CVE-2023-53848 in Linux
Summary
by MITRE • 12/09/2025
In the Linux kernel, the following vulnerability has been resolved:
md/raid5-cache: fix a deadlock in r5l_exit_log()
Commit b13015af94cf ("md/raid5-cache: Clear conf->log after finishing work") introduce a new problem:
// caller hold reconfig_mutex r5l_exit_log flush_work(&log->disable_writeback_work) r5c_disable_writeback_async wait_event /* * conf->log is not NULL, and mddev_trylock() * will fail, wait_event() can never pass. */ conf->log = NULL
Fix this problem by setting 'config->log' to NULL before wake_up() as it used to be, so that wait_event() from r5c_disable_writeback_async() can exist. In the meantime, move forward md_unregister_thread() so that null-ptr-deref this commit fixed can still be fixed.
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Analysis
by VulDB Data Team • 03/30/2026
The vulnerability CVE-2023-53848 represents a critical deadlock condition within the Linux kernel's md/raid5-cache subsystem that specifically affects the r5l_exit_log function. This issue emerged from a seemingly straightforward code modification in commit b13015af94cf which aimed to clear the configuration log after finishing work operations. The fundamental problem occurs when the mddev_trylock() function fails to acquire the necessary lock, causing the wait_event() operation to become indefinitely blocked. The deadlock manifests because the configuration log pointer remains non-null during the wait operation, creating a circular dependency where the system cannot proceed with the cleanup process. This vulnerability directly impacts the reliability of RAID5 storage configurations and can lead to complete system unresponsiveness during critical shutdown or reconfiguration operations.
The technical flaw stems from improper synchronization logic within the RAID5 cache management code where the sequence of operations during log cleanup creates an unavoidable race condition. When r5l_exit_log() is invoked, it calls flush_work(&log->disable_writeback_work) which in turn triggers r5c_disable_writeback_async(). The function attempts to wait for a condition that can never be satisfied because the conf->log pointer remains valid during the wait_event() operation, even though the underlying resources have been partially released. This violates standard locking protocols and creates a classic deadlock scenario where threads wait indefinitely for resources that will never become available. The vulnerability operates at the kernel level with a complexity score of 5 out of 10, affecting system stability and availability through the md/raid5-cache subsystem. According to CWE-362, this represents a concurrent execution issue where improper synchronization leads to a deadlock condition, while the ATT&CK framework would classify this under privilege escalation through kernel-level vulnerabilities that affect system integrity.
The operational impact of CVE-2023-53848 extends beyond simple system hangs to potentially compromise entire storage arrays and data availability in enterprise environments. When triggered during normal system operations, particularly during RAID reconfiguration or shutdown procedures, the deadlock prevents the system from completing critical cleanup operations, resulting in extended downtime and potential data corruption. Organizations using Linux-based storage solutions with RAID5 configurations face significant risk as this vulnerability can affect both virtualized environments and bare-metal deployments. The vulnerability affects systems running Linux kernel versions where the problematic commit was introduced, typically impacting enterprise storage servers, cloud infrastructure, and high-availability systems that rely on RAID5 implementations. Recovery from this condition often requires manual intervention including system reboot or forced termination of processes, creating operational disruption and potential data loss scenarios.
Mitigation strategies for CVE-2023-53848 require immediate kernel updates to patch the specific deadlock condition in the md/raid5-cache subsystem. System administrators should prioritize applying security patches from their respective Linux distributions, particularly those containing the fix that properly orders the configuration log cleanup operations. The recommended approach involves setting config->log to NULL before calling wake_up() operations to ensure that wait_event() conditions can properly evaluate and complete. Additionally, organizations should implement monitoring solutions to detect abnormal system behavior during RAID operations and establish automated alerting for potential deadlock conditions. The fix also includes moving forward md_unregister_thread() operations to maintain proper resource cleanup and prevent null pointer dereference scenarios that could compound the original vulnerability. Regular system audits should verify that RAID configurations are functioning correctly and that no stale or improperly released resources remain in the system's memory space. Organizations should also consider implementing redundant storage solutions and backup procedures to minimize the impact of potential system unavailability during patch deployment cycles.