================================================================== BUG: KASAN: use-after-free in __fire_sched_out_preempt_notifiers kernel/sched/core.c:2550 [inline] BUG: KASAN: use-after-free in fire_sched_out_preempt_notifiers kernel/sched/core.c:2558 [inline] BUG: KASAN: use-after-free in prepare_task_switch kernel/sched/core.c:2594 [inline] BUG: KASAN: use-after-free in context_switch kernel/sched/core.c:2765 [inline] BUG: KASAN: use-after-free in __schedule+0xda3/0x2060 kernel/sched/core.c:3376 Read of size 8 at addr ffff8801be539718 by task syzkaller940820/8273 CPU: 1 PID: 8273 Comm: syzkaller940820 Not tainted 4.15.0-rc4-mm1+ #47 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:355 [inline] kasan_report+0x23b/0x360 mm/kasan/report.c:413 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:434 __fire_sched_out_preempt_notifiers kernel/sched/core.c:2550 [inline] fire_sched_out_preempt_notifiers kernel/sched/core.c:2558 [inline] prepare_task_switch kernel/sched/core.c:2594 [inline] context_switch kernel/sched/core.c:2765 [inline] __schedule+0xda3/0x2060 kernel/sched/core.c:3376 preempt_schedule_common+0x22/0x60 kernel/sched/core.c:3515 _cond_resched+0x1d/0x30 kernel/sched/core.c:4852 __wait_for_common kernel/sched/completion.c:107 [inline] wait_for_common kernel/sched/completion.c:123 [inline] wait_for_completion+0xa5/0x770 kernel/sched/completion.c:144 __synchronize_srcu+0x1ad/0x260 kernel/rcu/srcutree.c:925 synchronize_srcu_expedited kernel/rcu/srcutree.c:950 [inline] synchronize_srcu+0x1a3/0x570 kernel/rcu/srcutree.c:1001 kvm_page_track_unregister_notifier+0x186/0x270 arch/x86/kvm/page_track.c:213 kvm_mmu_uninit_vm+0x1c/0x20 arch/x86/kvm/mmu.c:5053 kvm_arch_destroy_vm+0x73b/0x980 arch/x86/kvm/x86.c:8418 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:729 [inline] kvm_put_kvm+0x695/0xde0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:750 kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:761 __fput+0x327/0x7e0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:869 do_group_exit+0x149/0x400 kernel/exit.c:972 get_signal+0x73f/0x16c0 kernel/signal.c:2337 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x94/0x96 RIP: 0033:0x44d2f7 RSP: 002b:00007f03146d3d18 EFLAGS: 00000206 ORIG_RAX: 000000000000001c RAX: 0000000000000000 RBX: 00007f03146d4700 RCX: 000000000044d2f7 RDX: 0000000000000004 RSI: 00000000007fb000 RDI: 00007f0313ed4000 RBP: 0000000000000000 R08: 00007f03146d4700 R09: 00007f03146d4700 R10: 00007f03146d4700 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ffe7791824f R14: 00007f03146d49c0 R15: 0000000000000000 Allocated by task 8272: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3541 kmem_cache_zalloc include/linux/slab.h:695 [inline] vmx_create_vcpu+0xc4/0x2f20 arch/x86/kvm/vmx.c:9819 kvm_arch_vcpu_create+0x12c/0x1a0 arch/x86/kvm/x86.c:7884 kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:2446 [inline] kvm_vm_ioctl+0x48b/0x1c60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2944 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x1f/0x96 Freed by task 8273: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3485 [inline] kmem_cache_free+0x83/0x2a0 mm/slab.c:3743 vmx_free_vcpu+0x1ee/0x260 arch/x86/kvm/vmx.c:9813 kvm_arch_vcpu_free arch/x86/kvm/x86.c:7870 [inline] kvm_free_vcpus arch/x86/kvm/x86.c:8317 [inline] kvm_arch_destroy_vm+0x4a2/0x980 arch/x86/kvm/x86.c:8416 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:729 [inline] kvm_put_kvm+0x695/0xde0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:750 kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:761 __fput+0x327/0x7e0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:869 do_group_exit+0x149/0x400 kernel/exit.c:972 get_signal+0x73f/0x16c0 kernel/signal.c:2337 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x94/0x96 The buggy address belongs to the object at ffff8801be539700 which belongs to the cache kvm_vcpu of size 23872 The buggy address is located 24 bytes inside of 23872-byte region [ffff8801be539700, ffff8801be53f440) The buggy address belongs to the page: page:ffffea0006f94e00 count:1 mapcount:0 mapping:ffff8801be539700 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff8801be539700 0000000000000000 0000000100000001 raw: ffffea0006f91e20 ffff8801d6da4f48 ffff8801d6d90840 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801be539600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801be539680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801be539700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801be539780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801be539800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================