Re: [PATCH] PM: acquire device locks prior to suspending

Alan Stern
2007-12-14T16:49:35Z

On Thu, 13 Dec 2007, Andrew Morton wrote:

> hm, that was all fairly helpful. <looks at the document> <erk, long>
>
> This:

> gives me this:
>
> http://userweb.kernel.org/~akpm/pc131699.jpg
>
> which identifies your culprit: msr.
>
> I'd suggest that the above debug patch be turned into some
> boot-option-enabled thing and that it be rolled out with this locking
> change for a while at least.

Rafael, that looks like exactly the same sort of problem as we saw
before. Global searching for CPU_DEAD_FROZEN shows several other
places that perhaps also could be simplified; the actions they take may
or may not be needed for hibernation.

The following three seem definitely dangerous:

arch/x86/kernel/cpu/mcheck/mce_64.c
arch/x86/kernel/cpuid.c
arch/x86/kernel/msr.c

And of course the third is the one that Andrew spotted. Would you like
to address them? I can package up Andrew's debugging changes into a
real patch.

Alan Stern