Re: [rcu:dev.2020.06.02a 67/90] kernel/rcu/rcuperf.c:727:38: warning: format specifies type 'size_t' (aka 'unsigned int') but the argument has type 'unsigned long'
From: Nathan Chancellor
Date: Sun Jun 07 2020 - 23:26:51 EST
On Mon, Jun 08, 2020 at 09:56:16AM +0800, Kefeng Wang wrote:
>
> On 2020/6/8 3:00, Paul E. McKenney wrote:
> > On Fri, Jun 05, 2020 at 05:19:14PM -0700, Paul E. McKenney wrote:
> > > On Sat, Jun 06, 2020 at 07:07:10AM +0800, kernel test robot wrote:
> > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2020.06.02a
> > > > head: 5216948905dd07a84cef8a7dc72c2ec076802efd
> > > > commit: 7d16add62717136b1839f0b3d7ea4cbb98f38c2a [67/90] rcuperf: Fix kfree_mult to match printk() format
> > > > config: arm-randconfig-r004-20200605 (attached as .config)
> > > > compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 6dd738e2f0609f7d3313b574a1d471263d2d3ba1)
> > > > reproduce (this is a W=1 build):
> > > > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > > > chmod +x ~/bin/make.cross
> > > > # install arm cross compiling tool for clang build
> > > > # apt-get install binutils-arm-linux-gnueabi
> > > > git checkout 7d16add62717136b1839f0b3d7ea4cbb98f38c2a
> > > > # save the attached .config to linux build tree
> > > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm
> > > >
> > > > If you fix the issue, kindly add following tag as appropriate
> > > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > Adding Kefeng on CC. Kefeng, thoughts?
> > Like this, perhaps?
>
> Hi PaulïI check https://lkml.org/lkml/2020/6/2/286 and <https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/log/?h=dev.2020.06.02a>
>
> https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/log/?h=dev.2020.06.02a
>
> There are two different ways to fix the same issue
>
> patch 1:Â rcuperf: Fix printk format warning urgent-for-mingo
>
> patch 2:Â 'rcuperf: Fix kfree_mult to match printk() format' from IngoÂ
> after my patch
>
> since patch1 already merged, patch2 is not needed, so skip patch2?
>
> Thanks.
>
>
>
>
> >
> > Thanx, Paul
> >
> > diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
> > index 962869d..dc7483a 100644
> > --- a/kernel/rcu/rcuperf.c
> > +++ b/kernel/rcu/rcuperf.c
> > @@ -724,7 +724,7 @@ kfree_perf_init(void)
> > schedule_timeout_uninterruptible(1);
> > }
> > - pr_alert("kfree object size=%zu\n", kfree_mult * sizeof(struct kfree_obj));
> > + pr_alert("kfree object size=%zu\n", (size_t)kfree_mult * sizeof(struct kfree_obj));
> > kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
> > GFP_KERNEL);
> >
> > > > All warnings (new ones prefixed by >>, old ones prefixed by <<):
> > > >
> > > > > > kernel/rcu/rcuperf.c:727:38: warning: format specifies type 'size_t' (aka 'unsigned int') but the argument has type 'unsigned long' [-Wformat]
> > > > pr_alert("kfree object size=%zun", kfree_mult * sizeof(struct kfree_obj));
> > > > ~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > %lu
> > > > include/linux/printk.h:295:35: note: expanded from macro 'pr_alert'
> > > > printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
> > > > ~~~ ^~~~~~~~~~~
> > > > 1 warning generated.
> > > >
> > > > vim +727 kernel/rcu/rcuperf.c
> > > >
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 709)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 710) static int __init
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 711) kfree_perf_init(void)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 712) {
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 713) long i;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 714) int firsterr = 0;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 715)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 716) kfree_nrealthreads = compute_real(kfree_nthreads);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 717) /* Start up the kthreads. */
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 718) if (shutdown) {
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 719) init_waitqueue_head(&shutdown_wq);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 720) firsterr = torture_create_kthread(kfree_perf_shutdown, NULL,
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 721) shutdown_task);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 722) if (firsterr)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 723) goto unwind;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 724) schedule_timeout_uninterruptible(1);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 725) }
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 726)
> > > > b3e2d20973db3e Kefeng Wang 2020-04-17 @727 pr_alert("kfree object size=%zu\n", kfree_mult * sizeof(struct kfree_obj));
> > > > f87dc808009ac8 Joel Fernandes (Google 2020-03-16 728)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 729) kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 730) GFP_KERNEL);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 731) if (kfree_reader_tasks == NULL) {
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 732) firsterr = -ENOMEM;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 733) goto unwind;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 734) }
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 735)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 736) for (i = 0; i < kfree_nrealthreads; i++) {
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 737) firsterr = torture_create_kthread(kfree_perf_thread, (void *)i,
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 738) kfree_reader_tasks[i]);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 739) if (firsterr)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 740) goto unwind;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 741) }
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 742)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 743) while (atomic_read(&n_kfree_perf_thread_started) < kfree_nrealthreads)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 744) schedule_timeout_uninterruptible(1);
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 745)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 746) torture_init_end();
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 747) return 0;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 748)
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 749) unwind:
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 750) torture_init_end();
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 751) kfree_perf_cleanup();
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 752) return firsterr;
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 753) }
> > > > e6e78b004fa7e0 Joel Fernandes (Google 2019-08-30 754)
> > > >
> > > > :::::: The code at line 727 was first introduced by commit
> > > > :::::: b3e2d20973db3ec87a6dd2fee0c88d3c2e7c2f61 rcuperf: Fix printk format warning
> > > >
> > > > :::::: TO: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> > > > :::::: CC: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > > >
> > > > ---
> > > > 0-DAY CI Kernel Test Service, Intel Corporation
> > > > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
> > >
> > .
> >
>
Agreed, this is a problem with both patches being applied together,
both GCC and clang agree: https://godbolt.org/z/gGzPV7
Either patch works, it is just a matter of deciding which is better.
Cheers,
Nathan