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To: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>,
 linuxppc-dev@lists.ozlabs.org
From: Michael Ellerman <patch-notifications@ellerman.id.au>
Cc: anju@linux.vnet.ibm.com, paulus@samba.org, gpiccoli@linux.vnet.ibm.com
Subject: Re: powerpc/perf: Fix IMC allocation routine
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Date: Wed,  1 Nov 2017 16:17:42 +1100 (AEDT)
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On Thu, 2017-10-19 at 19:41:33 UTC, "Guilherme G. Piccoli" wrote:
> When setting nr_cpus=1, we observed a crash in IMC code during boot
> due to a missing allocation: basically, IMC code is taking the number
> of threads into account in imc_mem_init() and if we manually set
> nr_cpus for a value that is not multiple of the number of threads per
> core, an integer division in that function will discard the decimal
> portion, leading IMC to not allocate one mem_info struct. This causes
> a NULL pointer dereference later, on is_core_imc_mem_inited().
> 
> This patch just rounds that division up, fixing the bug.
> 
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/0b167f11085a34281349f395d20005

cheers