Re: [kbuild-all] Re: kernel/rcu/tree.c:2073:23: warning: stack frame size of 2704 bytes in function 'rcu_gp_kthread'

[Rong Chen]

On 6/6/21 12:49 PM, Paul E. McKenney wrote:
> On Sun, Jun 06, 2021 at 12:19:57PM +0800, kernel test robot wrote:
> > Hi Paul,
> >
> > FYI, the error/warning still remains.
> >
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   f5b6eb1e018203913dfefcf6fa988649ad11ad6e
> > commit: 7dffe01765d9309b8bd5505503933ec0ec53d192 rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros
> > date:   5 months ago
> > config: powerpc-randconfig-r023-20210606 (attached as .config)
> > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 551a697c5cf33275b66add4fc467fcf59084cffb)
> > 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 powerpc cross compiling tool for clang build
> >          # apt-get install binutils-powerpc-linux-gnu
> >          # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7dffe01765d9309b8bd5505503933ec0ec53d192
> >          git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >          git fetch --no-tags linus master
> >          git checkout 7dffe01765d9309b8bd5505503933ec0ec53d192
> >          # save the attached .config to linux build tree
> >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > All warnings (new ones prefixed by >>):
> >
> >     In file included from kernel/rcu/tree.c:21:
> >     In file included from include/linux/kernel.h:12:
> >     In file included from include/linux/bitops.h:29:
> >     In file included from arch/powerpc/include/asm/bitops.h:62:
> >     arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined]
> >     #define __lwsync()      __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory")
> >             ^
> >     <built-in>:310:9: note: previous definition is here
> >     #define __lwsync __builtin_ppc_lwsync
> >             ^
> > > > kernel/rcu/tree.c:2073:23: warning: stack frame size of 2704 bytes in function 'rcu_gp_kthread' [-Wframe-larger-than=]
> >     static int __noreturn rcu_gp_kthread(void *unused)
> Does -rcu commit 2f20de99a63b ("rcu: Make rcu_gp_cleanup() be noinline
> for tracing") help?

Hi Paul,

The stack frame size decreased to 2256 bytes:

  kernel/rcu/tree.c:2129:23: warning: stack frame size of 2256 bytes in 
function 'rcu_gp_kthread' [-Wframe-larger-than=]

Best Regards,
Rong Chen