Resending with more folks added. On Sat, Aug 17, 2019 at 05:10:59AM +0800, kbuild test robot wrote: > tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/paulmck/linux-rcu.git from-joel.2019.08.16a > head: 01b0e4d3e0ac279b295bc06a3591f0b810b9908f > commit: bda80ba9decc7a32413e88d2f070de180c4b76ab [143/172] rcu/tree: Add basic support for kfree_rcu() batching > config: riscv-defconfig (attached as .config) > compiler: riscv64-linux-gcc (GCC) 7.4.0 > reproduce: > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout bda80ba9decc7a32413e88d2f070de180c4b76ab > # save the attached .config to linux build tree > GCC_VERSION=7.4.0 make.cross ARCH=riscv This seems to be a riscv issue: A call to '__compiletime_assert_2792' declared with attribute error: BUILD_BUG failed Could riscv folks take a look at it? Why is using xchg() causing issues? The xchg() is being done on a bool. thanks, - Joel > If you fix the issue, kindly add following tag > Reported-by: kbuild test robot <lkp@xxxxxxxxx> > > All error/warnings (new ones prefixed by >>): > > In file included from arch/riscv/include/asm/atomic.h:19:0, > from include/linux/atomic.h:7, > from include/linux/spinlock.h:445, > from kernel/rcu/tree.c:23: > kernel/rcu/tree.c: In function 'kfree_rcu_monitor': > >> arch/riscv/include/asm/cmpxchg.h:140:2: warning: '__ret' is used uninitialized in this function [-Wuninitialized] > __ret; \ > ^~~~~ > arch/riscv/include/asm/cmpxchg.h:121:21: note: '__ret' was declared here > __typeof__(*(ptr)) __ret; \ > ^ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > >> kernel/rcu/tree.c:2808:6: note: in expansion of macro 'xchg' > if (xchg(&krcp->monitor_todo, false)) > ^~~~ > In file included from include/linux/kernel.h:11:0, > from kernel/rcu/tree.c:21: > >> include/linux/compiler.h:350:38: error: call to '__compiletime_assert_2808' declared with attribute error: BUILD_BUG failed > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' > prefix ## suffix(); \ > ^~~~~~ > include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") > ^~~~~~~~~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:138:3: note: in expansion of macro 'BUILD_BUG' > BUILD_BUG(); \ > ^~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > >> kernel/rcu/tree.c:2808:6: note: in expansion of macro 'xchg' > if (xchg(&krcp->monitor_todo, false)) > ^~~~ > In function 'kfree_rcu_drain_unlock', > inlined from 'kfree_rcu_monitor' at kernel/rcu/tree.c:2809:3: > include/linux/compiler.h:350:38: error: call to '__compiletime_assert_2792' declared with attribute error: BUILD_BUG failed > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' > prefix ## suffix(); \ > ^~~~~~ > include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") > ^~~~~~~~~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:138:3: note: in expansion of macro 'BUILD_BUG' > BUILD_BUG(); \ > ^~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > kernel/rcu/tree.c:2792:7: note: in expansion of macro 'xchg' > if (!xchg(&krcp->monitor_todo, true)) > ^~~~ > kernel/rcu/tree.c: In function 'kfree_call_rcu': > >> kernel/rcu/tree.c:2860:5: warning: '__ret' may be used uninitialized in this function [-Wmaybe-uninitialized] > if (!xchg(&krcp->monitor_todo, true)) > ^ > In file included from include/linux/kernel.h:11:0, > from kernel/rcu/tree.c:21: > include/linux/compiler.h:350:38: error: call to '__compiletime_assert_2860' declared with attribute error: BUILD_BUG failed > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' > prefix ## suffix(); \ > ^~~~~~ > include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") > ^~~~~~~~~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:138:3: note: in expansion of macro 'BUILD_BUG' > BUILD_BUG(); \ > ^~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > kernel/rcu/tree.c:2860:7: note: in expansion of macro 'xchg' > if (!xchg(&krcp->monitor_todo, true)) > ^~~~ > -- > In file included from arch/riscv/include/asm/atomic.h:19:0, > from include/linux/atomic.h:7, > from include/linux/spinlock.h:445, > from kernel//rcu/tree.c:23: > kernel//rcu/tree.c: In function 'kfree_rcu_monitor': > >> arch/riscv/include/asm/cmpxchg.h:140:2: warning: '__ret' is used uninitialized in this function [-Wuninitialized] > __ret; \ > ^~~~~ > arch/riscv/include/asm/cmpxchg.h:121:21: note: '__ret' was declared here > __typeof__(*(ptr)) __ret; \ > ^ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > kernel//rcu/tree.c:2808:6: note: in expansion of macro 'xchg' > if (xchg(&krcp->monitor_todo, false)) > ^~~~ > In file included from include/linux/kernel.h:11:0, > from kernel//rcu/tree.c:21: > >> include/linux/compiler.h:350:38: error: call to '__compiletime_assert_2808' declared with attribute error: BUILD_BUG failed > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' > prefix ## suffix(); \ > ^~~~~~ > include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") > ^~~~~~~~~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:138:3: note: in expansion of macro 'BUILD_BUG' > BUILD_BUG(); \ > ^~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > kernel//rcu/tree.c:2808:6: note: in expansion of macro 'xchg' > if (xchg(&krcp->monitor_todo, false)) > ^~~~ > In function 'kfree_rcu_drain_unlock', > inlined from 'kfree_rcu_monitor' at kernel//rcu/tree.c:2809:3: > include/linux/compiler.h:350:38: error: call to '__compiletime_assert_2792' declared with attribute error: BUILD_BUG failed > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' > prefix ## suffix(); \ > ^~~~~~ > include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") > ^~~~~~~~~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:138:3: note: in expansion of macro 'BUILD_BUG' > BUILD_BUG(); \ > ^~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > kernel//rcu/tree.c:2792:7: note: in expansion of macro 'xchg' > if (!xchg(&krcp->monitor_todo, true)) > ^~~~ > kernel//rcu/tree.c: In function 'kfree_call_rcu': > kernel//rcu/tree.c:2860:5: warning: '__ret' may be used uninitialized in this function [-Wmaybe-uninitialized] > if (!xchg(&krcp->monitor_todo, true)) > ^ > In file included from include/linux/kernel.h:11:0, > from kernel//rcu/tree.c:21: > include/linux/compiler.h:350:38: error: call to '__compiletime_assert_2860' declared with attribute error: BUILD_BUG failed > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^ > include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' > prefix ## suffix(); \ > ^~~~~~ > include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) > ^~~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~~~~~~~~~~~~~~~ > include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") > ^~~~~~~~~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:138:3: note: in expansion of macro 'BUILD_BUG' > BUILD_BUG(); \ > ^~~~~~~~~ > >> arch/riscv/include/asm/cmpxchg.h:146:23: note: in expansion of macro '__xchg' > (__typeof__(*(ptr))) __xchg((ptr), _x_, sizeof(*(ptr))); \ > ^~~~~~ > kernel//rcu/tree.c:2860:7: note: in expansion of macro 'xchg' > if (!xchg(&krcp->monitor_todo, true)) > ^~~~ > > vim +/xchg +2808 kernel/rcu/tree.c > > 2776 > 2777 static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp, > 2778 unsigned long flags) > 2779 { > 2780 /* Flush ->head to ->head_free, all objects on ->head_free will be > 2781 * kfree'd after a grace period. > 2782 */ > 2783 if (queue_kfree_rcu_work(krcp)) { > 2784 /* Success! Our job is done here. */ > 2785 spin_unlock_irqrestore(&krcp->lock, flags); > 2786 return; > 2787 } > 2788 > 2789 /* Previous batch that was queued to RCU did not get free yet, let us > 2790 * try again soon. > 2791 */ > > 2792 if (!xchg(&krcp->monitor_todo, true)) > 2793 schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); > 2794 spin_unlock_irqrestore(&krcp->lock, flags); > 2795 } > 2796 > 2797 /* > 2798 * This function is invoked after the KFREE_DRAIN_JIFFIES timeout has elapsed, > 2799 * and it drains the specified kfree_rcu_cpu structure's ->head list. > 2800 */ > 2801 static void kfree_rcu_monitor(struct work_struct *work) > 2802 { > 2803 unsigned long flags; > 2804 struct kfree_rcu_cpu *krcp = container_of(work, struct kfree_rcu_cpu, > 2805 monitor_work.work); > 2806 > 2807 spin_lock_irqsave(&krcp->lock, flags); > > 2808 if (xchg(&krcp->monitor_todo, false)) > 2809 kfree_rcu_drain_unlock(krcp, flags); > 2810 else > 2811 spin_unlock_irqrestore(&krcp->lock, flags); > 2812 } > 2813 > 2814 /* > 2815 * This version of kfree_call_rcu does not do batching of kfree_rcu() requests. > 2816 * Used only by rcuperf torture test for comparison with kfree_rcu_batch(). > 2817 */ > 2818 void kfree_call_rcu_nobatch(struct rcu_head *head, rcu_callback_t func) > 2819 { > 2820 __call_rcu(head, func, 1); > 2821 } > 2822 EXPORT_SYMBOL_GPL(kfree_call_rcu_nobatch); > 2823 > 2824 /* > 2825 * Queue a request for lazy invocation of kfree() after a grace period. > 2826 * > 2827 * Each kfree_call_rcu() request is added to a batch. The batch will be drained > 2828 * every KFREE_DRAIN_JIFFIES number of jiffies. All the objects in the batch > 2829 * will be kfree'd in workqueue context. This allows us to: > 2830 * > 2831 * 1. Batch requests together to reduce the number of grace periods during > 2832 * heavy kfree_rcu() load. > 2833 * > 2834 * 2. In the future, makes it possible to use kfree_bulk() on a large number of > 2835 * kfree_rcu() requests thus reducing the per-object overhead of kfree() and > 2836 * also reducing cache misses. > 2837 */ > 2838 void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func) > 2839 { > 2840 unsigned long flags; > 2841 struct kfree_rcu_cpu *krcp; > 2842 > 2843 /* kfree_call_rcu() batching requires timers to be up. If the scheduler > 2844 * is not yet up, just skip batching and do the non-batched version. > 2845 */ > 2846 if (rcu_scheduler_active != RCU_SCHEDULER_RUNNING) > 2847 return kfree_call_rcu_nobatch(head, func); > 2848 > 2849 head->func = func; > 2850 > 2851 local_irq_save(flags); /* For safely calling this_cpu_ptr(). */ > 2852 krcp = this_cpu_ptr(&krc); > 2853 spin_lock(&krcp->lock); > 2854 > 2855 /* Queue the kfree but don't yet schedule the batch. */ > 2856 head->next = krcp->head; > 2857 krcp->head = head; > 2858 > 2859 /* Schedule monitor for timely drain after KFREE_DRAIN_JIFFIES. */ > > 2860 if (!xchg(&krcp->monitor_todo, true)) > 2861 schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES); > 2862 > 2863 spin_unlock(&krcp->lock); > 2864 local_irq_restore(flags); > 2865 } > 2866 EXPORT_SYMBOL_GPL(kfree_call_rcu); > 2867 > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation
