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Can I call printk() when interrupts are disabled?

April 26, 2017disabled interrupts printk

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Can I call printk() when interrupts are disabled?

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• (REG) Yes, you can, although you should be careful. Older kernels had the infamous cli()-sti() pair in printk(), so you would get enabled interrupts when returning from printk(), whether printk() was called with interrupts disabled or enabled; whereas recent kernels (e.g. 2.1.107) restore the flags when printk() is finished. You have to know which version of the kernel you are coding for. Read the Source, Luke. Also note that in 2.2.x kernels, printk() grabs a spinlock for SMP machines to avoid any possible deadlocks.