From: Paolo Bonzini <pbonzini@redhat.com> To: Elena Reshetova <elena.reshetova@intel.com>, linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, x86@kernel.org, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com, hpa@zytor.com, Hans Liljestrand <ishkamiel@gmail.com>, Kees Cook <keescook@chromium.org>, David Windsor <dwindsor@gmail.com> Subject: Re: [PATCH 4/4] kvm: convert kvm.users_count from atomic_t to refcount_t Date: Mon, 20 Feb 2017 12:37:15 +0100 [thread overview] Message-ID: <220f229f-0e3e-2a72-62c1-1677021c3987@redhat.com> (raw) In-Reply-To: <1487588781-15123-5-git-send-email-elena.reshetova@intel.com> On 20/02/2017 12:06, Elena Reshetova wrote: > refcount_t type and corresponding API should be > used instead of atomic_t when the variable is used as > a reference counter. This allows to avoid accidental > refcounter overflows that might lead to use-after-free > situations. > > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> > Signed-off-by: Kees Cook <keescook@chromium.org> > Signed-off-by: David Windsor <dwindsor@gmail.com> Looks good, will apply after the merge window. Paolo > --- > include/linux/kvm_host.h | 3 ++- > virt/kvm/kvm_main.c | 8 ++++---- > 2 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index cda457b..7fa05a5 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -26,6 +26,7 @@ > #include <linux/context_tracking.h> > #include <linux/irqbypass.h> > #include <linux/swait.h> > +#include <linux/refcount.h> > #include <asm/signal.h> > > #include <linux/kvm.h> > @@ -402,7 +403,7 @@ struct kvm { > #endif > struct kvm_vm_stat stat; > struct kvm_arch arch; > - atomic_t users_count; > + refcount_t users_count; > #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET > struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; > spinlock_t ring_lock; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index dcd1c12..6ae5775 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -622,7 +622,7 @@ static struct kvm *kvm_create_vm(unsigned long type) > mutex_init(&kvm->lock); > mutex_init(&kvm->irq_lock); > mutex_init(&kvm->slots_lock); > - atomic_set(&kvm->users_count, 1); > + refcount_set(&kvm->users_count, 1); > INIT_LIST_HEAD(&kvm->devices); > > r = kvm_arch_init_vm(kvm, type); > @@ -745,13 +745,13 @@ static void kvm_destroy_vm(struct kvm *kvm) > > void kvm_get_kvm(struct kvm *kvm) > { > - atomic_inc(&kvm->users_count); > + refcount_inc(&kvm->users_count); > } > EXPORT_SYMBOL_GPL(kvm_get_kvm); > > void kvm_put_kvm(struct kvm *kvm) > { > - if (atomic_dec_and_test(&kvm->users_count)) > + if (refcount_dec_and_test(&kvm->users_count)) > kvm_destroy_vm(kvm); > } > EXPORT_SYMBOL_GPL(kvm_put_kvm); > @@ -3640,7 +3640,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, > * To avoid the race between open and the removal of the debugfs > * directory we test against the users count. > */ > - if (!atomic_add_unless(&stat_data->kvm->users_count, 1, 0)) > + if (!refcount_inc_not_zero(&stat_data->kvm->users_count)) > return -ENOENT; > > if (simple_attr_open(inode, file, get, set, fmt)) { >
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com> To: Elena Reshetova <elena.reshetova@intel.com>, linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, x86@kernel.org, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com, hpa@zytor.com, Hans Liljestrand <ishkamiel@gmail.com>, Kees Cook <keescook@chromium.org>, David Windsor <dwindsor@gmail.com> Subject: Re: [PATCH 4/4] kvm: convert kvm.users_count from atomic_t to refcount_t Date: Mon, 20 Feb 2017 11:37:15 +0000 [thread overview] Message-ID: <220f229f-0e3e-2a72-62c1-1677021c3987@redhat.com> (raw) In-Reply-To: <1487588781-15123-5-git-send-email-elena.reshetova@intel.com> On 20/02/2017 12:06, Elena Reshetova wrote: > refcount_t type and corresponding API should be > used instead of atomic_t when the variable is used as > a reference counter. This allows to avoid accidental > refcounter overflows that might lead to use-after-free > situations. > > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> > Signed-off-by: Kees Cook <keescook@chromium.org> > Signed-off-by: David Windsor <dwindsor@gmail.com> Looks good, will apply after the merge window. Paolo > --- > include/linux/kvm_host.h | 3 ++- > virt/kvm/kvm_main.c | 8 ++++---- > 2 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index cda457b..7fa05a5 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -26,6 +26,7 @@ > #include <linux/context_tracking.h> > #include <linux/irqbypass.h> > #include <linux/swait.h> > +#include <linux/refcount.h> > #include <asm/signal.h> > > #include <linux/kvm.h> > @@ -402,7 +403,7 @@ struct kvm { > #endif > struct kvm_vm_stat stat; > struct kvm_arch arch; > - atomic_t users_count; > + refcount_t users_count; > #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET > struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; > spinlock_t ring_lock; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index dcd1c12..6ae5775 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -622,7 +622,7 @@ static struct kvm *kvm_create_vm(unsigned long type) > mutex_init(&kvm->lock); > mutex_init(&kvm->irq_lock); > mutex_init(&kvm->slots_lock); > - atomic_set(&kvm->users_count, 1); > + refcount_set(&kvm->users_count, 1); > INIT_LIST_HEAD(&kvm->devices); > > r = kvm_arch_init_vm(kvm, type); > @@ -745,13 +745,13 @@ static void kvm_destroy_vm(struct kvm *kvm) > > void kvm_get_kvm(struct kvm *kvm) > { > - atomic_inc(&kvm->users_count); > + refcount_inc(&kvm->users_count); > } > EXPORT_SYMBOL_GPL(kvm_get_kvm); > > void kvm_put_kvm(struct kvm *kvm) > { > - if (atomic_dec_and_test(&kvm->users_count)) > + if (refcount_dec_and_test(&kvm->users_count)) > kvm_destroy_vm(kvm); > } > EXPORT_SYMBOL_GPL(kvm_put_kvm); > @@ -3640,7 +3640,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, > * To avoid the race between open and the removal of the debugfs > * directory we test against the users count. > */ > - if (!atomic_add_unless(&stat_data->kvm->users_count, 1, 0)) > + if (!refcount_inc_not_zero(&stat_data->kvm->users_count)) > return -ENOENT; > > if (simple_attr_open(inode, file, get, set, fmt)) { >
next prev parent reply other threads:[~2017-02-20 11:37 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-02-20 11:06 [PATCH 0/4] arch subsystem refcounter conversions Elena Reshetova 2017-02-20 11:06 ` Elena Reshetova 2017-02-20 11:06 ` [PATCH 1/4] s390: convert debug_info.ref_count from atomic_t to refcount_t Elena Reshetova 2017-02-20 11:06 ` Elena Reshetova 2017-02-20 13:24 ` Heiko Carstens 2017-02-20 13:24 ` Heiko Carstens 2017-02-20 13:34 ` Heiko Carstens 2017-02-20 13:34 ` Heiko Carstens 2017-02-20 13:35 ` Reshetova, Elena 2017-02-20 13:39 ` Peter Zijlstra 2017-02-20 13:39 ` Peter Zijlstra 2017-02-20 11:06 ` [PATCH 2/4] x86: convert threshold_bank.cpus " Elena Reshetova 2017-02-20 11:06 ` Elena Reshetova 2017-02-20 11:17 ` Borislav Petkov 2017-02-20 11:17 ` Borislav Petkov 2017-02-20 12:20 ` Reshetova, Elena 2017-02-20 12:20 ` Reshetova, Elena 2017-02-20 12:30 ` Borislav Petkov 2017-02-20 12:30 ` Borislav Petkov 2017-02-21 20:45 ` Kees Cook 2017-02-21 20:45 ` Kees Cook 2017-02-22 9:27 ` Borislav Petkov 2017-02-22 9:27 ` Borislav Petkov 2017-02-20 11:06 ` [PATCH 3/4] sparc: convert mdesc_handle.refcnt " Elena Reshetova 2017-02-20 11:06 ` Elena Reshetova 2017-02-20 14:56 ` David Miller 2017-02-20 14:56 ` David Miller 2017-04-03 7:28 ` Reshetova, Elena 2017-04-03 7:28 ` Reshetova, Elena 2017-04-03 13:12 ` David Miller 2017-04-03 13:12 ` David Miller 2017-04-03 16:06 ` Reshetova, Elena 2017-04-03 16:06 ` Reshetova, Elena 2017-04-03 16:16 ` David Miller 2017-04-03 16:16 ` David Miller 2017-02-20 11:06 ` [PATCH 4/4] kvm: convert kvm.users_count " Elena Reshetova 2017-02-20 11:06 ` Elena Reshetova 2017-02-20 11:37 ` Paolo Bonzini [this message] 2017-02-20 11:37 ` Paolo Bonzini 2017-02-20 12:22 ` Reshetova, Elena 2017-02-20 12:22 ` Reshetova, Elena
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