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

On Mon, Jun 07, 2021 at 05:18:21PM +0800, Rong Chen wrote: > > 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... >>> 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(a)intel.com&gt; >>> >>> 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=] Very good, thank you! Does the following patch (in addition to that commit) also help?

Thanx, Paul ------------------------------------------------------------------------ diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 13bd8eee62bf..ef435aeac993 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1737,7 +1737,7 @@ static void rcu_strict_gp_boundary(void *unused) /* * Initialize a new grace period. Return false if no grace period required. */ -static bool rcu_gp_init(void) +static noinline bool rcu_gp_init(void) { unsigned long firstseq; unsigned long flags; @@ -1931,7 +1931,7 @@ static void rcu_gp_fqs(bool first_time) /* * Loop doing repeated quiescent-state forcing until the grace period ends. */ -static void rcu_gp_fqs_loop(void) +static noinline void rcu_gp_fqs_loop(void) { bool first_gp_fqs; int gf = 0;