From: Len Baker <len.baker@gmx.com>
To: Paul Mackerras <paulus@ozlabs.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Len Baker <len.baker@gmx.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Kees Cook <keescook@chromium.org>,
kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] KVM: PPC: Replace zero-length array with flexible array member
Date: Sat, 18 Sep 2021 16:21:38 +0200 [thread overview]
Message-ID: <20210918142138.17709-1-len.baker@gmx.com> (raw)
There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use "flexible array members" [1] for these cases. The
older style of one-element or zero-length arrays should no longer be
used[2].
Also, make use of the struct_size() helper in kzalloc().
[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
Signed-off-by: Len Baker <len.baker@gmx.com>
---
arch/powerpc/include/asm/kvm_host.h | 2 +-
arch/powerpc/kvm/book3s_64_vio.c | 3 +--
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 080a7feb7731..3aed653373a5 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -190,7 +190,7 @@ struct kvmppc_spapr_tce_table {
u64 size; /* window size in pages */
struct list_head iommu_tables;
struct mutex alloc_lock;
- struct page *pages[0];
+ struct page *pages[];
};
/* XICS components, defined in book3s_xics.c */
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index 6365087f3160..d42b4b6d4a79 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -295,8 +295,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
return ret;
ret = -ENOMEM;
- stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *),
- GFP_KERNEL);
+ stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL);
if (!stt)
goto fail_acct;
--
2.25.1
next reply other threads:[~2021-09-18 14:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-18 14:21 Len Baker [this message]
2021-09-21 0:05 ` [PATCH] KVM: PPC: Replace zero-length array with flexible array member Gustavo A. R. Silva
2021-10-20 23:28 ` Gustavo A. R. Silva
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