This commit fixes a "maybe-uninitialized" build failure in
arch/mips/kvm/tlb.c when KVM, DYNAMIC_DEBUG and JUMP_LABEL are all
enabled. The failure is:
In file included from ./include/linux/printk.h:329:0,
from ./include/linux/kernel.h:13,
from ./include/asm-generic/bug.h:15,
from ./arch/mips/include/asm/bug.h:41,
from ./include/linux/bug.h:4,
from ./include/linux/thread_info.h:11,
from ./include/asm-generic/current.h:4,
from ./arch/mips/include/generated/asm/current.h:1,
from ./include/linux/sched.h:11,
from arch/mips/kvm/tlb.c:13:
arch/mips/kvm/tlb.c: In function ‘kvm_mips_host_tlb_inv’:
./include/linux/dynamic_debug.h:126:3: error: ‘idx_kernel’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
__dynamic_pr_debug(&descriptor, pr_fmt(fmt), \
^~~~~~~~~~~~~~~~~~
arch/mips/kvm/tlb.c:169:16: note: ‘idx_kernel’ was declared here
int idx_user, idx_kernel;
^~~~~~~~~~
There is a similar error relating to "idx_user". Both errors were
observed with GCC 6.
As far as I can tell, it is impossible for either idx_user or idx_kernel
to be uninitialized when they are later read in the calls to kvm_debug,
but to satisfy the compiler, add zero initializers to both variables.
Signed-off-by: James Cowgill <James.Cowgill@xxxxxxxxxx>
Fixes: 57e3869cfaae ("KVM: MIPS/TLB: Generalise host TLB invalidate to kernel ASID")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.11+
---
arch/mips/kvm/tlb.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c
index 7c6336dd2638..7cd92166a0b9 100644
--- a/arch/mips/kvm/tlb.c
+++ b/arch/mips/kvm/tlb.c
@@ -166,7 +166,11 @@ static int _kvm_mips_host_tlb_inv(unsigned long entryhi)
int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va,
bool user, bool kernel)
{
- int idx_user, idx_kernel;
+ /*
+ * Initialize idx_user and idx_kernel to workaround bogus
+ * maybe-initialized warning when using GCC 6.
+ */
+ int idx_user = 0, idx_kernel = 0;
unsigned long flags, old_entryhi;
local_irq_save(flags);
--
2.11.0
