[frederic-dynticks:rcu/context-tracking 13/19] kernel/context_tracking.c:91:25: error: implicit declaration of function 'rcu_irq_work_resched'

From: kernel test robot
Date: Wed Mar 02 2022 - 19:08:23 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git rcu/context-tracking
head: e4eaff86ec91c1cbde9a113cf5232dac9f897337
commit: 5cb63f8df32ee1a43ca46337d6c8554a27d44165 [13/19] rcu/context-tracking: Move deferred nocb resched to context tracking
config: arm-randconfig-c002-20220302 (https://download.01.org/0day-ci/archive/20220303/202203030631.Za0lAbtO-lkp@xxxxxxxxx/config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0
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=5cb63f8df32ee1a43ca46337d6c8554a27d44165
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 5cb63f8df32ee1a43ca46337d6c8554a27d44165
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

kernel/context_tracking.c: In function '__ct_user_enter':
>> kernel/context_tracking.c:91:25: error: implicit declaration of function 'rcu_irq_work_resched' [-Werror=implicit-function-declaration]
91 | rcu_irq_work_resched();
| ^~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors


vim +/rcu_irq_work_resched +91 kernel/context_tracking.c

51
52 /**
53 * __ct_user_enter - Inform the context tracking that the CPU is going
54 * to enter user or guest space mode.
55 *
56 * This function must be called right before we switch from the kernel
57 * to user or guest space, when it's guaranteed the remaining kernel
58 * instructions to execute won't use any RCU read side critical section
59 * because this function sets RCU in extended quiescent state.
60 */
61 void noinstr __ct_user_enter(enum ctx_state state)
62 {
63 lockdep_assert_irqs_disabled();
64
65 /* Kernel threads aren't supposed to go to userspace */
66 WARN_ON_ONCE(!current->mm);
67
68 if (!context_tracking_recursion_enter())
69 return;
70
71 if ( __this_cpu_read(context_tracking.state) != state) {
72 if (__this_cpu_read(context_tracking.active)) {
73 /*
74 * At this stage, only low level arch entry code remains and
75 * then we'll run in userspace. We can assume there won't be
76 * any RCU read-side critical section until the next call to
77 * user_exit() or ct_irq_enter(). Let's remove RCU's dependency
78 * on the tick.
79 */
80 if (state == CONTEXT_USER) {
81 instrumentation_begin();
82 trace_user_enter(0);
83 vtime_user_enter(current);
84 instrumentation_end();
85 }
86 /*
87 * Other than generic entry implementation, we may be past the last
88 * rescheduling opportunity in the entry code. Trigger a self IPI
89 * that will fire and reschedule once we resume in user/guest mode.
90 */
> 91 rcu_irq_work_resched();
92 rcu_user_enter();
93 }
94 /*
95 * Even if context tracking is disabled on this CPU, because it's outside
96 * the full dynticks mask for example, we still have to keep track of the
97 * context transitions and states to prevent inconsistency on those of
98 * other CPUs.
99 * If a task triggers an exception in userspace, sleep on the exception
100 * handler and then migrate to another CPU, that new CPU must know where
101 * the exception returns by the time we call exception_exit().
102 * This information can only be provided by the previous CPU when it called
103 * exception_enter().
104 * OTOH we can spare the calls to vtime and RCU when context_tracking.active
105 * is false because we know that CPU is not tickless.
106 */
107 __this_cpu_write(context_tracking.state, state);
108 }
109 context_tracking_recursion_exit();
110 }
111 EXPORT_SYMBOL_GPL(__ct_user_enter);
112

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