From: Fabiano Rosas <farosas@linux.ibm.com> To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy <aik@ozlabs.ru>, kvm-ppc@vger.kernel.org Subject: Re: [PATCH kernel] KVM: PPC: Book3S: Suppress warnings when allocating too big memory slots Date: Wed, 01 Sep 2021 11:59:47 -0300 [thread overview] Message-ID: <87fsuouysc.fsf@linux.ibm.com> (raw) In-Reply-To: <20210901084512.1658628-1-aik@ozlabs.ru> Alexey Kardashevskiy <aik@ozlabs.ru> writes: > The userspace can trigger "vmalloc size %lu allocation failure: exceeds > total pages" via the KVM_SET_USER_MEMORY_REGION ioctl. > > This silences the warning by checking the limit before calling vzalloc() > and returns ENOMEM if failed. > > This does not call underlying valloc helpers as __vmalloc_node() is only > exported when CONFIG_TEST_VMALLOC_MODULE and __vmalloc_node_range() is not > exported at all. > > Spotted by syzkaller. > > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > --- > arch/powerpc/kvm/book3s_hv.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 474c0cfde384..a59f1cccbcf9 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -4830,8 +4830,12 @@ static int kvmppc_core_prepare_memory_region_hv(struct kvm *kvm, > unsigned long npages = mem->memory_size >> PAGE_SHIFT; > > if (change == KVM_MR_CREATE) { > - slot->arch.rmap = vzalloc(array_size(npages, > - sizeof(*slot->arch.rmap))); > + unsigned long cb = array_size(npages, sizeof(*slot->arch.rmap)); What does cb mean? > + > + if ((cb >> PAGE_SHIFT) > totalram_pages()) > + return -ENOMEM; > + > + slot->arch.rmap = vzalloc(cb); > if (!slot->arch.rmap) > return -ENOMEM; > }
WARNING: multiple messages have this Message-ID (diff)
From: Fabiano Rosas <farosas@linux.ibm.com> To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy <aik@ozlabs.ru>, kvm-ppc@vger.kernel.org Subject: Re: [PATCH kernel] KVM: PPC: Book3S: Suppress warnings when allocating too big memory slots Date: Wed, 01 Sep 2021 14:59:47 +0000 [thread overview] Message-ID: <87fsuouysc.fsf@linux.ibm.com> (raw) In-Reply-To: <20210901084512.1658628-1-aik@ozlabs.ru> Alexey Kardashevskiy <aik@ozlabs.ru> writes: > The userspace can trigger "vmalloc size %lu allocation failure: exceeds > total pages" via the KVM_SET_USER_MEMORY_REGION ioctl. > > This silences the warning by checking the limit before calling vzalloc() > and returns ENOMEM if failed. > > This does not call underlying valloc helpers as __vmalloc_node() is only > exported when CONFIG_TEST_VMALLOC_MODULE and __vmalloc_node_range() is not > exported at all. > > Spotted by syzkaller. > > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > --- > arch/powerpc/kvm/book3s_hv.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 474c0cfde384..a59f1cccbcf9 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -4830,8 +4830,12 @@ static int kvmppc_core_prepare_memory_region_hv(struct kvm *kvm, > unsigned long npages = mem->memory_size >> PAGE_SHIFT; > > if (change = KVM_MR_CREATE) { > - slot->arch.rmap = vzalloc(array_size(npages, > - sizeof(*slot->arch.rmap))); > + unsigned long cb = array_size(npages, sizeof(*slot->arch.rmap)); What does cb mean? > + > + if ((cb >> PAGE_SHIFT) > totalram_pages()) > + return -ENOMEM; > + > + slot->arch.rmap = vzalloc(cb); > if (!slot->arch.rmap) > return -ENOMEM; > }
next prev parent reply other threads:[~2021-09-01 15:00 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-01 8:45 [PATCH kernel] KVM: PPC: Book3S: Suppress warnings when allocating too big memory slots Alexey Kardashevskiy 2021-09-01 8:45 ` Alexey Kardashevskiy 2021-09-01 14:59 ` Fabiano Rosas [this message] 2021-09-01 14:59 ` Fabiano Rosas 2021-09-02 4:25 ` Alexey Kardashevskiy 2021-09-02 4:25 ` Alexey Kardashevskiy 2021-09-02 13:08 ` Fabiano Rosas 2021-09-02 13:08 ` Fabiano Rosas 2021-09-02 13:23 ` David Laight 2021-09-02 13:23 ` David Laight 2021-12-15 0:40 ` Michael Ellerman 2021-12-15 0:40 ` Michael Ellerman 2021-09-01 8:45 [PATCH kernel] KVM: PPC: Book3S: Suppress failed alloc warning in H_COPY_TOFROM_GUEST Alexey Kardashevskiy 2021-09-01 8:45 ` Alexey Kardashevskiy 2021-09-01 14:45 ` Fabiano Rosas 2021-09-01 14:45 ` Fabiano Rosas 2021-12-15 0:40 ` Michael Ellerman 2021-12-15 0:40 ` Michael Ellerman
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