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

From: Paul E. McKenney
Date: Sun Jun 06 2021 - 00:49:29 EST

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?

Thanx, Paul

> 2 warnings generated.
>
>
> vim +/rcu_gp_kthread +2073 kernel/rcu/tree.c
>
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2069
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2070 /*
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2071 * Body of kthread that handles grace periods.
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2072 */
> 0854a05c9fa554 kernel/rcu/tree.c Paul E. McKenney 2018-07-03 @2073 static int __noreturn rcu_gp_kthread(void *unused)
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2074 {
> 5871968d531f39 kernel/rcu/tree.c Paul E. McKenney 2015-02-24 2075 rcu_bind_gp_kthread();
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2076 for (;;) {
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2077
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2078 /* Handle grace-period start. */
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2079 for (;;) {
> 0f11ad323dd3d3 kernel/rcu/tree.c Paul E. McKenney 2020-02-10 2080 trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
> 63c4db78e80407 kernel/rcutree.c Paul E. McKenney 2013-08-09 2081 TPS("reqwait"));
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2082 rcu_state.gp_state = RCU_GP_WAIT_GPS;
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2083 swait_event_idle_exclusive(rcu_state.gp_wq,
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2084 READ_ONCE(rcu_state.gp_flags) &
> 4cdfc175c25c89 kernel/rcutree.c Paul E. McKenney 2012-06-22 2085 RCU_GP_FLAG_INIT);
> 55b2dcf5870004 kernel/rcu/tree.c Paul E. McKenney 2020-04-01 2086 rcu_gp_torture_wait();
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2087 rcu_state.gp_state = RCU_GP_DONE_GPS;
> 78e4bc34e5d966 kernel/rcu/tree.c Paul E. McKenney 2013-09-24 2088 /* Locking provides needed memory barrier. */
> 0854a05c9fa554 kernel/rcu/tree.c Paul E. McKenney 2018-07-03 2089 if (rcu_gp_init())
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2090 break;
> cee43939893337 kernel/rcu/tree.c Paul E. McKenney 2018-03-02 2091 cond_resched_tasks_rcu_qs();
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2092 WRITE_ONCE(rcu_state.gp_activity, jiffies);
> 73a860cd58a1eb kernel/rcu/tree.c Paul E. McKenney 2014-08-14 2093 WARN_ON(signal_pending(current));
> 0f11ad323dd3d3 kernel/rcu/tree.c Paul E. McKenney 2020-02-10 2094 trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
> 63c4db78e80407 kernel/rcutree.c Paul E. McKenney 2013-08-09 2095 TPS("reqwaitsig"));
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2096 }
> 7fdefc10e1d730 kernel/rcutree.c Paul E. McKenney 2012-06-22 2097
> 4cdfc175c25c89 kernel/rcutree.c Paul E. McKenney 2012-06-22 2098 /* Handle quiescent-state forcing. */
> c3854a055bc834 kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2099 rcu_gp_fqs_loop();
> 4cdfc175c25c89 kernel/rcutree.c Paul E. McKenney 2012-06-22 2100
> 4cdfc175c25c89 kernel/rcutree.c Paul E. McKenney 2012-06-22 2101 /* Handle grace-period end. */
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2102 rcu_state.gp_state = RCU_GP_CLEANUP;
> 0854a05c9fa554 kernel/rcu/tree.c Paul E. McKenney 2018-07-03 2103 rcu_gp_cleanup();
> 9cbc5b97029bff kernel/rcu/tree.c Paul E. McKenney 2018-07-05 2104 rcu_state.gp_state = RCU_GP_CLEANED;
> 4cdfc175c25c89 kernel/rcutree.c Paul E. McKenney 2012-06-22 2105 }
> b3dbec76e5334f kernel/rcutree.c Paul E. McKenney 2012-06-18 2106 }
> b3dbec76e5334f kernel/rcutree.c Paul E. McKenney 2012-06-18 2107
>
> :::::: The code at line 2073 was first introduced by commit
> :::::: 0854a05c9fa554930174f0fa7453c18f99108a4a rcu: Remove rsp parameter from rcu_gp_kthread() and friends
>
> :::::: TO: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> :::::: CC: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx