From: Nathan Chancellor <natechancellor@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Roman Kagan" <rkagan@virtuozzo.com>,
"Liran Alon" <liran.alon@oracle.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com
Subject: Re: [PATCH] [v3] x86: kvm: avoid -Wsometimes-uninitized warning
Date: Fri, 12 Jul 2019 10:44:54 -0700 [thread overview]
Message-ID: <20190712174454.GA3845@archlinux-threadripper> (raw)
In-Reply-To: <20190712141322.1073650-1-arnd@arndb.de>
On Fri, Jul 12, 2019 at 04:13:09PM +0200, Arnd Bergmann wrote:
> Clang notices a code path in which some variables are never
> initialized, but fails to figure out that this can never happen
> on i386 because is_64_bit_mode() always returns false.
>
> arch/x86/kvm/hyperv.c:1610:6: error: variable 'ingpa' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> if (!longmode) {
> ^~~~~~~~~
> arch/x86/kvm/hyperv.c:1632:55: note: uninitialized use occurs here
> trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);
> ^~~~~
> arch/x86/kvm/hyperv.c:1610:2: note: remove the 'if' if its condition is always true
> if (!longmode) {
> ^~~~~~~~~~~~~~~
> arch/x86/kvm/hyperv.c:1595:18: note: initialize the variable 'ingpa' to silence this warning
> u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
> ^
> = 0
> arch/x86/kvm/hyperv.c:1610:6: error: variable 'outgpa' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> arch/x86/kvm/hyperv.c:1610:6: error: variable 'param' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
>
> Flip the condition around to avoid the conditional execution on i386.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
next prev parent reply other threads:[~2019-07-12 17:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 14:13 [PATCH] [v3] x86: kvm: avoid -Wsometimes-uninitized warning Arnd Bergmann
2019-07-12 16:33 ` Roman Kagan
2019-07-12 17:44 ` Nathan Chancellor [this message]
2019-07-12 17:45 ` Paolo Bonzini
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