CVE-2024-58090 is a vulnerability identified in the Linux kernel's scheduler core, specifically affecting the PREEMPT_NONE and PREEMPT_VOLUNTARY scheduling models. The issue arises from improper handling of rescheduling when interrupts are disabled. During the kernel's kexec jump process, a warning was observed indicating that interrupts were enabled after the irqrouter_resume function, which should not occur. The root cause is that within the interrupt-disabled section of the kexec jump, a syscore_suspend() callback wakes up a task, setting the NEED_RESCHED flag. Later, during the resume path, cond_resched() is invoked, which triggers the scheduler to run in an invalid context where interrupts are disabled. This leads to the scheduler enabling interrupts after a context switch, causing warnings and potentially unstable behavior. The problem is longstanding but has become more visible due to recent printk changes. The vulnerability does not affect the fully preemptible scheduling model (PREEMPT_RT) because cond_resched() is disabled there and preemption checks consider the interrupt-disabled state. The fix involves adding a check in cond_resched() to prevent scheduling when interrupts are disabled. This vulnerability could cause kernel instability or crashes during system reboot or kexec operations, especially on systems using the affected scheduling models. No known exploits are reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels with PREEMPT_NONE or PREEMPT_VOLUNTARY scheduling models, which are common in many server and embedded environments. The issue could lead to kernel warnings, instability, or crashes during critical operations such as system reboot or kexec jumps, potentially causing downtime or service interruptions. This is particularly impactful for data centers, cloud providers, and enterprises relying on Linux-based infrastructure for critical workloads. While it does not directly lead to privilege escalation or remote code execution, the instability could be exploited by attackers to cause denial of service or disrupt operations. Organizations with high availability requirements or those operating critical infrastructure should be especially cautious. Since the vulnerability is triggered during system reboot or kernel execution transitions, it may also affect automated update and recovery processes, increasing operational risk.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2024-58090 as soon as it becomes available. In the interim, system administrators should audit their kernel configurations to identify if PREEMPT_NONE or PREEMPT_VOLUNTARY scheduling models are in use and consider migrating to fully preemptible kernels (PREEMPT_RT) where feasible, as these are not affected. Additionally, organizations should carefully monitor kernel logs for warnings related to interrupts and scheduler activity, especially during reboot or kexec operations, to detect potential exploitation or instability. Testing kernel updates in staging environments before deployment can help avoid unexpected downtime. For embedded or specialized systems where kernel updates are delayed, applying vendor-specific patches or workarounds that disable problematic syscore_suspend()/resume() callbacks may reduce risk. Finally, maintaining robust backup and recovery procedures will mitigate operational impact if instability occurs.