[frederic-dynticks:rcu/context-tracking 14/19] kernel/rcu/tree.c:634:6: error: redefinition of '__rcu_irq_enter_check_tick'
From: kernel test robot
Date: Wed Mar 02 2022 - 17:41:06 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git rcu/context-tracking
head: e4eaff86ec91c1cbde9a113cf5232dac9f897337
commit: 5a91f02835a27bd066154ab87408505806710e19 [14/19] rcu/context-tracking: Move RCU-dynticks internal functions to context_tracking
config: hexagon-randconfig-r001-20220302 (https://download.01.org/0day-ci/archive/20220303/202203030604.SXPvt45B-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
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
# https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git/commit/?id=5a91f02835a27bd066154ab87408505806710e19
git remote add frederic-dynticks https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
git fetch --no-tags frederic-dynticks rcu/context-tracking
git checkout 5a91f02835a27bd066154ab87408505806710e19
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash kernel/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All errors (new ones prefixed by >>):
In file included from kernel/rcu/tree.c:65:
include/linux/context_tracking.h:106:30: error: incomplete result type 'enum ctx_state' in function definition
static inline enum ctx_state exception_enter(void) { return 0; }
^
include/linux/context_tracking.h:106:20: note: forward declaration of 'enum ctx_state'
static inline enum ctx_state exception_enter(void) { return 0; }
^
include/linux/context_tracking.h:106:61: error: returning 'int' from a function with incompatible result type 'enum ctx_state'
static inline enum ctx_state exception_enter(void) { return 0; }
^
include/linux/context_tracking.h:107:50: error: variable has incomplete type 'enum ctx_state'
static inline void exception_exit(enum ctx_state prev_ctx) { }
^
include/linux/context_tracking.h:106:20: note: forward declaration of 'enum ctx_state'
static inline enum ctx_state exception_enter(void) { return 0; }
^
include/linux/context_tracking.h:108:30: error: incomplete result type 'enum ctx_state' in function definition
static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
^
include/linux/context_tracking.h:106:20: note: forward declaration of 'enum ctx_state'
static inline enum ctx_state exception_enter(void) { return 0; }
^
include/linux/context_tracking.h:108:54: error: use of undeclared identifier 'CONTEXT_DISABLED'; did you mean 'CPU_SMT_DISABLED'?
static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
^~~~~~~~~~~~~~~~
CPU_SMT_DISABLED
include/linux/cpu.h:205:2: note: 'CPU_SMT_DISABLED' declared here
CPU_SMT_DISABLED,
^
In file included from kernel/rcu/tree.c:65:
include/linux/context_tracking.h:108:54: error: returning 'int' from a function with incompatible result type 'enum ctx_state'
static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
^~~~~~~~~~~~~~~~
>> kernel/rcu/tree.c:634:6: error: redefinition of '__rcu_irq_enter_check_tick'
void __rcu_irq_enter_check_tick(void)
^
include/linux/hardirq.h:19:20: note: previous definition is here
static inline void __rcu_irq_enter_check_tick(void) { }
^
In file included from kernel/rcu/tree.c:4457:
>> kernel/rcu/tree_plugin.h:932:13: error: static declaration of 'rcu_preempt_deferred_qs' follows non-static declaration
static void rcu_preempt_deferred_qs(struct task_struct *t)
^
include/linux/rcutree.h:63:6: note: previous declaration is here
void rcu_preempt_deferred_qs(struct task_struct *t);
^
8 errors generated.
vim +/__rcu_irq_enter_check_tick +634 kernel/rcu/tree.c
07325d4a90d2d8 kernel/rcu/tree.c Thomas Gleixner 2020-05-21 607
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 608 /**
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 609 * __rcu_irq_enter_check_tick - Enable scheduler tick on CPU if RCU needs it.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 610 *
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 611 * The scheduler tick is not normally enabled when CPUs enter the kernel
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 612 * from nohz_full userspace execution. After all, nohz_full userspace
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 613 * execution is an RCU quiescent state and the time executing in the kernel
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 614 * is quite short. Except of course when it isn't. And it is not hard to
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 615 * cause a large system to spend tens of seconds or even minutes looping
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 616 * in the kernel, which can cause a number of problems, include RCU CPU
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 617 * stall warnings.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 618 *
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 619 * Therefore, if a nohz_full CPU fails to report a quiescent state
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 620 * in a timely manner, the RCU grace-period kthread sets that CPU's
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 621 * ->rcu_urgent_qs flag with the expectation that the next interrupt or
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 622 * exception will invoke this function, which will turn on the scheduler
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 623 * tick, which will enable RCU to detect that CPU's quiescent states,
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 624 * for example, due to cond_resched() calls in CONFIG_PREEMPT=n kernels.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 625 * The tick will be disabled once a quiescent state is reported for
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 626 * this CPU.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 627 *
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 628 * Of course, in carefully tuned systems, there might never be an
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 629 * interrupt or exception. In that case, the RCU grace-period kthread
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 630 * will eventually cause one to happen. However, in less carefully
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 631 * controlled environments, this function allows RCU to get what it
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 632 * needs without creating otherwise useless interruptions.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 633 */
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 @634 void __rcu_irq_enter_check_tick(void)
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 635 {
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 636 struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 637
6dbce04d8417ae kernel/rcu/tree.c Peter Zijlstra 2020-11-16 638 // If we're here from NMI there's nothing to do.
6dbce04d8417ae kernel/rcu/tree.c Peter Zijlstra 2020-11-16 639 if (in_nmi())
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 640 return;
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 641
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 642 RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 643 "Illegal rcu_irq_enter_check_tick() from extended quiescent state");
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 644
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 645 if (!tick_nohz_full_cpu(rdp->cpu) ||
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 646 !READ_ONCE(rdp->rcu_urgent_qs) ||
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 647 READ_ONCE(rdp->rcu_forced_tick)) {
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 648 // RCU doesn't need nohz_full help from this CPU, or it is
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 649 // already getting that help.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 650 return;
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 651 }
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 652
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 653 // We get here only when not in an extended quiescent state and
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 654 // from interrupts (as opposed to NMIs). Therefore, (1) RCU is
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 655 // already watching and (2) The fact that we are in an interrupt
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 656 // handler and that the rcu_node lock is an irq-disabled lock
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 657 // prevents self-deadlock. So we can safely recheck under the lock.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 658 // Note that the nohz_full state currently cannot change.
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 659 raw_spin_lock_rcu_node(rdp->mynode);
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 660 if (rdp->rcu_urgent_qs && !rdp->rcu_forced_tick) {
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 661 // A nohz_full CPU is in the kernel and RCU needs a
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 662 // quiescent state. Turn on the tick!
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 663 WRITE_ONCE(rdp->rcu_forced_tick, true);
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 664 tick_dep_set_cpu(rdp->cpu, TICK_DEP_BIT_RCU);
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 665 }
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 666 raw_spin_unlock_rcu_node(rdp->mynode);
aaf2bc50df1f4b kernel/rcu/tree.c Paul E. McKenney 2020-05-21 667 }
64db4cfff99c04 kernel/rcutree.c Paul E. McKenney 2008-12-18 668
:::::: The code at line 634 was first introduced by commit
:::::: aaf2bc50df1f4bfc6857fc601fc7b21d5a18c6a1 rcu: Abstract out rcu_irq_enter_check_tick() from rcu_nmi_enter()
:::::: TO: Paul E. McKenney <paulmck@xxxxxxxxxx>
:::::: CC: Ingo Molnar <mingo@xxxxxxxxxx>
---
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