Re: [PATCH] kexec jump: fix compiling warning on xchg(&kexec_lock,0) in kernel_kexec()

From: Linus Torvalds
Date: Wed Aug 13 2008 - 16:32:30 EST




On Wed, 13 Aug 2008, Andrew Morton wrote:
>
> #2:

I thought you said there were things that want to sleep in the region?

If so, spinlocks will work as long as you don't have CONFIG_PREEMPT or
lock validation (there's no way to deadlock thanks to all the lock getters
using the "trylock" variant), but will blow up because a successful
trylock will obviously also disable preemption and/or trigger all the lock
detection.

So if there are potential sleepers, you'd need the mutex instead.

Linus
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