linux-kernel - [PATCH v3 0/2] KVM: s390: Fix two bugs

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Message-ID: <20250825151831.78221-1-imbrenda@linux.ibm.com>
Date: Mon, 25 Aug 2025 17:18:29 +0200
From: Claudio Imbrenda <imbrenda@...ux.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: linux-s390@...r.kernel.org, kvm@...r.kernel.org, david@...hat.com,
        frankja@...ux.ibm.com, seiden@...ux.ibm.com, nsg@...ux.ibm.com,
        nrb@...ux.ibm.com, schlameuss@...ux.ibm.com, hca@...ux.ibm.com,
        mhartmay@...ux.ibm.com, borntraeger@...ibm.com
Subject: [PATCH v3 0/2] KVM: s390: Fix two bugs

This small series fixes two bugs in s390 KVM. One is small and trivial,
the other is pretty bad.

* The wrong type of flag was being passed to vcpu_dat_fault_handler();
  it expects a FOLL_* flag, but a FAULT_FLAG_* was passed instead.
* Due to incorrect usage of mmu_notifier_register(), in some rare cases
  when running a secure guest, the struct mm for the userspace process
  would get freed too early and cause a use-after-free.

v2->v3
* Make sure .ops is not NULL before calling mmu_notifier_register() to
  avoid NULL pointer errors (thanks Marc)
v1->v2
* Rename the parameters of __kvm_s390_handle_dat_fault() and
  vcpu_dat_fault_handler() from flags to foll (thanks Christian)

Claudio Imbrenda (2):
  KVM: s390: Fix incorrect usage of mmu_notifier_register()
  KVM: s390: Fix FOLL_*/FAULT_FLAG_* confusion

 arch/s390/kvm/kvm-s390.c | 24 ++++++++++++------------
 arch/s390/kvm/pv.c       | 16 +++++++++++-----
 2 files changed, 23 insertions(+), 17 deletions(-)

-- 
2.51.0