Zack's Kernel News
Zack's Kernel News
Chronicler Zack Brown reports on the latest news, views, dilemmas, and developments within the Linux kernel community.
Working around Hardware Bugs
Some Linux kernel discussions can get pretty jaw-dropping. Andy Lutomirski proposed some code that would eliminate nested non-maskable interrupts (NMIs), which would ultimately allow a lot of kernel code to be removed. NMIs are signals that typically indicate some kind of hardware failure. They also typically can't be prevented by the operating system.
So far so good. However, one type of hardware error is the Machine-Check Exception (MCE), which indicates a problem with the CPU, and on Windows systems results in the blue screen of death. Andy's code had to account for various possibilities, such as an NMI followed immediately by an MCE. So, various kernel folks discussed the right way for Andy's code to handle these situations. Could the MCE interrupt the un-interruptable NMI? And so on.
At a certain point, Linus Torvalds joined the discussion, saying:
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