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In-Reply-To: <20180331140024.1610-1-mpe@ellerman.id.au>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@ozlabs.org
From: Michael Ellerman <patch-notifications@ellerman.id.au>
Cc: npiggin@gmail.com
Subject: Re: powerpc/mpic: Check if cpu_possible() in mpic_physmask()
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Date: Sun,  1 Apr 2018 01:05:47 +1100 (AEDT)
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On Sat, 2018-03-31 at 14:00:24 UTC, Michael Ellerman wrote:
> In mpic_physmask() we loop over all CPUs up to 32, then get the hard
> SMP processor id of that CPU.
> 
> Currently that's possibly walking off the end of the paca array, but
> in a future patch we will change the paca array to be an array of
> pointers, and in that case we will get a NULL for missing CPUs and
> oops. eg:
> 
>   Unable to handle kernel paging request for data at address 0x88888888888888b8
>   Faulting instruction address: 0xc00000000004e380
>   Oops: Kernel access of bad area, sig: 11 [#1]
>   ...
>   NIP .mpic_set_affinity+0x60/0x1a0
>   LR  .irq_do_set_affinity+0x48/0x100
> 
> Fix it by checking the CPU is possible, this also fixes the code if
> there are gaps in the CPU numbering which probably never happens on
> mpic systems but who knows.
> 
> Debugged-by: Nicholas Piggin <npiggin@gmail.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/0834d627fbea00c1444075eb3e448e

cheers