linux-kernel - [PATCH v2 0/4] Replace current->mm by kvm->mm on powerpc/kvm

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Date:   Thu,  7 Nov 2019 14:02:54 -0300
From:   Leonardo Bras <leonardo@...ux.ibm.com>
To:     kvm-ppc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Cc:     Leonardo Bras <leonardo@...ux.ibm.com>,
        Paul Mackerras <paulus@...abs.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH v2 0/4] Replace current->mm by kvm->mm on powerpc/kvm

By replacing, we would reduce the use of 'global' current on code,
relying more in the contents of kvm struct.

On code, I found that in kvm_create_vm() there is:
kvm->mm = current->mm;

And that on every kvm_*_ioctl we have tests like that:
if (kvm->mm != current->mm)
        return -EIO;

So this change would be safe.

Also, I fixed a possible 'use after free' of kvm variable in
kvm_vm_ioctl_create_spapr_tce, where it does a mutex_unlock(&kvm->lock)
after a kvm_put_kvm(kvm).

Changes since v1:
- Fixes possible 'use after free' on kvm_spapr_tce_release (from v1)
- Fixes possible 'use after free' on kvm_vm_ioctl_create_spapr_tce
- Fixes undeclared variable error

Build test:
- https://travis-ci.org/LeoBras/linux-ppc/builds/608807573

Leonardo Bras (4):
  powerpc/kvm/book3s: Fixes possible 'use after release' of kvm
  powerpc/kvm/book3s: Replace current->mm by kvm->mm
  powerpc/kvm/book3e: Replace current->mm by kvm->mm
  powerpc/kvm/e500: Replace current->mm by kvm->mm

 arch/powerpc/kvm/book3s_64_mmu_hv.c | 10 +++++-----
 arch/powerpc/kvm/book3s_64_vio.c    | 13 +++++++------
 arch/powerpc/kvm/book3s_hv.c        | 10 +++++-----
 arch/powerpc/kvm/booke.c            |  2 +-
 arch/powerpc/kvm/e500_mmu_host.c    |  6 +++---
 5 files changed, 21 insertions(+), 20 deletions(-)

-- 
2.23.0