Hi Vipin, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on db6e7adf8de9b3b99a9856acb73870cc3a70e3ca] url: https://github.com/0day-ci/linux/commits/Vipin-Sharma/KVM-Move-VM-s-worker-kthreads-back-to-the-original-cgroup-before-exiting/20220217-141723 base: db6e7adf8de9b3b99a9856acb73870cc3a70e3ca config: s390-randconfig-s032-20220217 (https://download.01.org/0day-ci/archive/20220217/202202172046.GuW8pHQc-lkp@xxxxxxxxx/config) compiler: s390-linux-gcc (GCC) 11.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/0day-ci/linux/commit/1abffef71ef85b6fb8f1296e6ef38febc4f2b007 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Vipin-Sharma/KVM-Move-VM-s-worker-kthreads-back-to-the-original-cgroup-before-exiting/20220217-141723 git checkout 1abffef71ef85b6fb8f1296e6ef38febc4f2b007 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=s390 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> sparse warnings: (new ones prefixed by >>) arch/s390/kvm/../../../virt/kvm/kvm_main.c: note: in included file: include/linux/kvm_host.h:1877:54: sparse: sparse: array of flexible structures include/linux/kvm_host.h:1879:56: sparse: sparse: array of flexible structures >> arch/s390/kvm/../../../virt/kvm/kvm_main.c:5859:54: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct task_struct *from @@ got struct task_struct [noderef] __rcu *real_parent @@ arch/s390/kvm/../../../virt/kvm/kvm_main.c:5859:54: sparse: expected struct task_struct *from arch/s390/kvm/../../../virt/kvm/kvm_main.c:5859:54: sparse: got struct task_struct [noderef] __rcu *real_parent arch/s390/kvm/../../../virt/kvm/kvm_main.c:2522:9: sparse: sparse: context imbalance in 'hva_to_pfn_remapped' - unexpected unlock vim +5859 arch/s390/kvm/../../../virt/kvm/kvm_main.c 5805 5806 static int kvm_vm_worker_thread(void *context) 5807 { 5808 /* 5809 * The init_context is allocated on the stack of the parent thread, so 5810 * we have to locally copy anything that is needed beyond initialization 5811 */ 5812 struct kvm_vm_worker_thread_context *init_context = context; 5813 struct kvm *kvm = init_context->kvm; 5814 kvm_vm_thread_fn_t thread_fn = init_context->thread_fn; 5815 uintptr_t data = init_context->data; 5816 int err, reattach_err; 5817 5818 err = kthread_park(current); 5819 /* kthread_park(current) is never supposed to return an error */ 5820 WARN_ON(err != 0); 5821 if (err) 5822 goto init_complete; 5823 5824 err = cgroup_attach_task_all(init_context->parent, current); 5825 if (err) { 5826 kvm_err("%s: cgroup_attach_task_all failed with err %d\n", 5827 __func__, err); 5828 goto init_complete; 5829 } 5830 5831 set_user_nice(current, task_nice(init_context->parent)); 5832 5833 init_complete: 5834 init_context->err = err; 5835 complete(&init_context->init_done); 5836 init_context = NULL; 5837 5838 if (err) 5839 goto out; 5840 5841 /* Wait to be woken up by the spawner before proceeding. */ 5842 kthread_parkme(); 5843 5844 if (!kthread_should_stop()) 5845 err = thread_fn(kvm, data); 5846 5847 out: 5848 /* 5849 * Move kthread back to its original cgroup to prevent it lingering in 5850 * the cgroup of the VM process, after the latter finishes its 5851 * execution. 5852 * 5853 * kthread_stop() waits on the 'exited' completion condition which is 5854 * set in exit_mm(), via mm_release(), in do_exit(). However, the 5855 * kthread is removed from the cgroup in the cgroup_exit() which is 5856 * called after the exit_mm(). This causes the kthread_stop() to return 5857 * before the kthread actually quits the cgroup. 5858 */ > 5859 reattach_err = cgroup_attach_task_all(current->real_parent, current); 5860 if (reattach_err) { 5861 kvm_err("%s: cgroup_attach_task_all failed on reattach with err %d\n", 5862 __func__, reattach_err); 5863 } 5864 return err; 5865 } 5866 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
