内核: 在启用 SMP 时, SysFS 发生死锁

We still have many issues when SMP is enabled, but this was the first time I saw this specific deadlock, so it seemed noteworthy. It is probably quite hard to reproduce, I only hit this bug once even if I used these steps many times (I was trying to repro another bug):

• Boot serenity with smp=on
• Not sure if this is relevant, but I used 8 cores
• I had at least one terminal doing loop { /usr/Tests/Kernel/TestKernelAlarm }
• And at least one instance of SystemMonitor running