From: Roman Kagan <rkagan@virtuozzo.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Denis V. Lunev" <den@openvz.org>,
kbuild test robot <fengguang.wu@intel.com>,
Andrey Smetanin <asmetanin@virtuozzo.com>, <kbuild-all@01.org>,
<kvm@vger.kernel.org>
Subject: Re: [kvm:queue 27/38] arch/x86/kvm/hyperv.c:186:41: sparse: incorrect type in argument 2 (different modifiers)
Date: Fri, 18 Sep 2015 17:40:27 +0300 [thread overview]
Message-ID: <20150918144026.GJ3317@rkaganb.sw.ru> (raw)
In-Reply-To: <55FC17B4.9060702@redhat.com>
On Fri, Sep 18, 2015 at 03:55:00PM +0200, Paolo Bonzini wrote:
>
>
> On 18/09/2015 15:51, Denis V. Lunev wrote:
> >> 185
> >> > 186 task_cputime_adjusted(current, &utime, &stime);
> >> 187 return div_u64(cputime_to_nsecs(utime + stime), 100);
> >> 188 }
> >> 189
> >> 190 static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr,
> >> u64 data, bool host)
> >> 191 {
> >> 192 struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;
> >> 193
> >> 194 switch (msr) {
> >>
> >> ---
> >> 0-DAY kernel test infrastructure Open Source Technology
> >> Center
> >> https://lists.01.org/pipermail/kbuild-all Intel
> >> Corporation
> > can not get an idea what is this warning about...
> > For me it looks pretty lame.
>
> I think it wants you to do
>
> - return div_u64(cputime_to_nsecs(utime + stime), 100);
> + return div_u64(cputime_to_nsecs(utime) +
> + cputime_to_nsecs(stime), 100);
The warning is pretty specific about the point where it triggered.
I have reduced it to the following standalone reproducer:
%%% cat x.c
#ifdef __CHECKER__
# define __nocast __attribute__((nocast))
#else
# define __nocast
#endif
typedef unsigned long __nocast cputime_t;
extern void task_cputime_adjusted(cputime_t *);
extern void current_task_runtime_100ns(void);
void current_task_runtime_100ns(void)
{
cputime_t utime;
task_cputime_adjusted(&utime);
}
%%% gcc -c x.c -Wall -Werror -O2; echo $?
0
%%% sparse x.c
x.c:16:32: warning: incorrect type in argument 1 (different modifiers)
x.c:16:32: expected unsigned long [nocast] [usertype] *<noident>
x.c:16:32: got unsigned long *<noident>
x.c:16:32: warning: implicit cast to nocast type
Looks like a sparse bug to me.
Roman.
next prev parent reply other threads:[~2015-09-18 14:40 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-18 13:39 [kvm:queue 27/38] arch/x86/kvm/hyperv.c:186:41: sparse: incorrect type in argument 2 (different modifiers) kbuild test robot
2015-09-18 13:51 ` Denis V. Lunev
2015-09-18 13:55 ` Paolo Bonzini
2015-09-18 13:57 ` Denis V. Lunev
2015-09-18 14:40 ` Roman Kagan [this message]
2015-09-18 14:41 ` Paolo Bonzini
2015-09-18 15:06 ` [kbuild-all] " Fengguang Wu
2016-01-05 13:51 ` Luc Van Oostenryck
2016-01-05 16:25 ` [PATCH] Do not drop 'nocast' modifier when taking the address Luc Van Oostenryck
2016-02-02 20:25 ` Christopher Li
2016-02-03 3:43 ` Luc Van Oostenryck
2016-02-03 4:09 ` Christopher Li
2016-02-03 9:15 ` Luc Van Oostenryck
2016-02-22 18:41 ` Christopher Li
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