svn commit: r313037 - in head/sys: amd64/include kern mips/include net powerpc/include sparc64/include

[Jason Harmening]

Can you post an example of such panic?  Only 2 MI pieces were changed,
netisr and rmlock.  I haven't seen problems on my own amd64/i386/arm
testing of this, so a backtrace might help to narrow down the cause.

On Sat, Feb 4, 2017 at 12:22 PM, Andreas Tobler <andreast at freebsd.org>
wrote:

> On 04.02.17 20:54, Jason Harmening wrote:
>
>> I suspect this broke rmlocks for mips because the rmlock implementation
>> takes the address of the per-CPU pc_rm_queue when building tracker
>> lists.  That address may be later accessed from another CPU and will
>> then translate to the wrong physical region if the address was taken
>> relative to the globally-constant pcpup VA used on mips.
>>
>> Regardless, for mips get_pcpup() should be implemented as
>> pcpu_find(curcpu) since returning an address that may mean something
>> different depending on the CPU seems like a big POLA violation if
>> nothing else.
>>
>> I'm more concerned about the report of powerpc breakage.  For powerpc we
>> simply take each pcpu pointer from the pc_allcpu list (which is the same
>> value stored in the cpuid_to_pcpu array) and pass it through the ap_pcpu
>> global to each AP's startup code, which then stores it in sprg0.  It
>> should be globally unique and won't have the variable-translation issues
>> seen on mips.   Andreas, are you certain this change was responsible the
>> breakage you saw, and was it the same sort of hang observed on mips?
>>
>
> I'm really sure. 313036 booted fine, allowed me to execute heavy
> compilation jobs, np. 313037 on the other side gave me various patterns of
> panics. During startup, but I also succeeded to get into multiuser and then
> the panic happend during port building.
>
> I have no deeper inside where pcpu data is used. Justin mentioned netisr?
>
> Andreas
>
>