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authorMichael S. Tsirkin <mst@redhat.com>2012-06-03 11:34:08 +0300
committerAvi Kivity <avi@redhat.com>2012-06-06 15:26:12 +0300
commit79f702a6d18c75760c68202007265b2310d6f44e (patch)
tree43cf82edcc521f2442927cfb8351816c6517e13f /arch/x86/kvm
parenta737f256bf14adf94920aa70d150ab4dcd145109 (diff)
downloadblackbird-op-linux-79f702a6d18c75760c68202007265b2310d6f44e.tar.gz
blackbird-op-linux-79f702a6d18c75760c68202007265b2310d6f44e.zip
KVM: disable uninitialized var warning
I see this in 3.5-rc1: arch/x86/kvm/mmu.c: In function ‘kvm_test_age_rmapp’: arch/x86/kvm/mmu.c:1271: warning: ‘iter.desc’ may be used uninitialized in this function The line in question was introduced by commit 1e3f42f03c38c29c1814199a6f0a2f01b919ea3f static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp, unsigned long data) { - u64 *spte; + u64 *sptep; + struct rmap_iterator iter; <- line 1271 int young = 0; /* The reason I think is that the compiler assumes that the rmap value could be 0, so static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter) { if (!rmap) return NULL; if (!(rmap & 1)) { iter->desc = NULL; return (u64 *)rmap; } iter->desc = (struct pte_list_desc *)(rmap & ~1ul); iter->pos = 0; return iter->desc->sptes[iter->pos]; } will not initialize iter.desc, but the compiler isn't smart enough to see that for (sptep = rmap_get_first(*rmapp, &iter); sptep; sptep = rmap_get_next(&iter)) { will immediately exit in this case. I checked by adding if (!*rmapp) goto out; on top which is clearly equivalent but disables the warning. This patch uses uninitialized_var to disable the warning without increasing code size. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/mmu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 1ca7164a74f1..24dd43d45ae4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1238,7 +1238,7 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct rmap_iterator uninitialized_var(iter);
int young = 0;
/*
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